In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on Roche/Hitachi cobas c systems.
Particle enhanced immunoturbidimetric assay.
Human lipoprotein (a) agglutinates with latex particles coated with anti‑Lp(a) antibodies. The precipitate is determined turbidimetrically at 800 / 660 nm.
Measuring range: 7‑240 nmol/L
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Limit of Blank | = 6 nmol/L |
Limit of Detection | = 7 nmol/L |
Limit of Quantitation | = 20 nmol/L |
The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 20 %. It has been determined using low concentration lipoprotein (a) samples.
A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The European Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
However the NHLBI recommends to stop using data for total Lp(a) mass, and to use nmol/L units instead, which consider the number of particles. Additionally they recommend to use assays independent from apo(a) size and standardized according to the IFCC reference material SRM2B.
Based on the evaluation of Framingham data values above 75 nmol/L are regarded as a cut‑off value for the presence of an increased risk.
Elevated Lp(a) levels can be found in most racial/ethnicity groups, with the prevalence being lowest in whites and Asians. The median Lp(a) levels in black subjects and in Asian Indians from southern locations are 2‑ to 4‑fold higher compared with whites, and up to 68 % of blacks have Lp(a) levels > 75 nmol/L, whereas levels above this threshold are present in around 25 % of whites.
Therefore reference ranges have not been established for this assay for different ethnic populations or disease states. Since Lp(a) levels are largely influenced by hereditary factors and vary with ethnic populations it is recommended that each laboratory establish own expected values.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 6 nmol/L of initial values of samples ≤ 60 nmol/L and within ± 10 % for samples > 60 nmol/L.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference from rheumatoid factors up to a concentration of 1200 IU/mL.
Plasminogen: No significant cross‑reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross‑reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 450 nmol/L.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on
|
| Analyzer(s) on which cobas c pack(s) can be used | |
08106126 190 | Tina‑quant Lipoprotein (a) Gen.2 (150 tests) | System‑ID 2086 001 | cobas c 503 |
Materials required (but not provided):
05852641 190 | Preciset Lp(a) Gen.2 (5 × 1 mL) | Codes 20962‑20966 | |
05852650 190 | PreciControl Lp(a) Gen.2 |
| |
08063494 190 | Diluent NaCl 9 % (123 mL) | System‑ID 2906 001 |
LPA2: ACN 20860
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
Reporting time | 10 min | ||
Wavelength (sub/main) | 800/660 nm | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 100 µL | – | |
R3 | 25 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 1.5 µL | – | – |
Decreased | 6.0 µL | 8 µL | 88 µL |
Increased | 1.5 µL | – | – |
For further information about the assay test definitions refer to the application parameters screen of the corresponding analyzer and assay.
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 26 weeks |
Calibrators | S1: H2O |
Calibration mode | Non-linear |
Calibration frequency | Automatic full calibration Full calibration |
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against the IFCC reference material SRM2B for nmol/L.
Representative performance data on the analyzers are given below. These data represent the performance of the analytical procedure itself.
Results obtained in individual laboratories may differ due to heterogenous sample materials, aging of analyzer components and mixture of reagents running on the analyzer.
Precision was determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP05‑A3 requirements with repeatability (n = 84) and intermediate precision (2 aliquots per run, 2 runs per day, 21 days). The following results were obtained:
Repeatability | Mean | SD | CV |
Lp (a) Control Level Low | 35.2 | 0.412 | 1.2 |
Lp (a) Control Level High | 97.7 | 0.435 | 0.4 |
Human serum 1 | 19.7 | 0.414 | 2.1 |
Human serum 2 | 49.3 | 0.516 | 1.0 |
Human serum 3 | 80.5 | 0.434 | 0.5 |
Human serum 4 | 120 | 0.546 | 0.5 |
Human serum 5 | 203 | 0.794 | 0.4 |
Intermediate precision | Mean | SD | CV |
Lp (a) Control Level Low | 35.1 | 0.562 | 1.6 |
Lp (a) Control Level High | 99.0 | 1.14 | 1.2 |
Human serum 1 | 19.7 | 0.508 | 2.6 |
Human serum 2 | 49.3 | 0.676 | 1.4 |
Human serum 3 | 80.5 | 0.831 | 1.0 |
Human serum 4 | 119 | 1.14 | 1.0 |
Human serum 5 | 203 | 1.33 | 0.7 |
Lipoprotein (a) values for human serum and plasma samples obtained on a cobas c 503 analyzer (y) were compared with those determined using the corresponding reagent on a cobas c 501 analyzer (x).
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.019x + 0.878 nmol/L | y = 1.010x + 1.34 nmol/L |
τ = 0.988 | r = 1.000 |
The sample concentrations were between 7.34 and 235 nmol/L.
Lipoprotein (a) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
Main problem for accurate detection of Lp(a) is the size polymorphism of apolipoprotein a (apo (a)). Levels of Lp(a) vary drastically among individuals and ethnic groups as the level is predominantly determined by the apo (a) gene on chromosome 6.
The high variable number of KRINGLE 4 type2 domains results in an apo (a) size ranging from 187 kDa to over 662 kDa. Assays with antibodies directed against this variable part of the Lp(a) molecule will underestimate Lp(a) in patients with apo (a) smaller than in the used calibrator and overestimate Lp(a) in such samples with larger apo (a) particles as in the calibrator. Based on the size heterogeneity it makes no sense to measure Lp(a) mass. Therefore the values should be expressed in terms of nanomoles per liter of Lp(a) protein.
Only standardization of these assays against an apo (a) size independent method will yield correct results. Such methods use antibodies that recognize a single copy of apo (a) per particle. By using the WHO/IFCC International Reference Reagent (SRM2B) this goal can be reached.
According to the European Atherosclerosis Society Lp(a) measurement should be recommended in selected cases at high risk and in subjects with a family history of premature cardio vascular disease.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; stabilizers; BSA; rabbit serum 0.1 %, preservative |
R3 | Latex particles coated with polyclonal anti‑human lipoprotein(a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3, BSA; preservative |
R1 is in position B and R3 is in position C.
For in vitro diagnostic use for health care professionals. Exercise the normal precautions required for handling all laboratory reagents.
Infectious or microbial waste:
Warning: handle waste as potentially biohazardous material. Dispose of waste according to accepted laboratory instructions and procedures.
Environmental hazards:
Apply all relevant local disposal regulations to determine the safe disposal.
Safety data sheet available for professional user on request.
For quality control, use control materials as listed in the “Order information” section. In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. It is recommended to perform quality control always after lot calibration and subsequently at least every 26 weeks. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li‑heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
See the limitations and interferences section for details about possible sample interferences.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
If samples are not assayed within 48 h,
In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on Roche/Hitachi cobas c systems. The measurement of Lp(a) is useful in evaluating lipid metabolism disorders and assessing atherosclerotic cardiovascular disease in specific populations, when used in conjunction with clinical evaluation and other lipoprotein tests.
Particle enhanced immunoturbidimetric assay.
Human lipoprotein (a) agglutinates with latex particles coated with anti‑Lp(a) antibodies. The precipitate is determined turbidimetrically at 800 / 660 nm.
Measuring range: 6.0‑80 mg/dL
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Limit of Blank | = 3 mg/dL |
Limit of Detection | = 4 mg/dL |
Limit of Quantitation | = 6 mg/dL |
The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 30 %. It has been determined using low concentration lipoprotein (a) samples.
The defined threshold of Lp(a) concentration at which individuals can be classified as being at increased risk varies greatly among studies, ranging from 20 mg/dL to 40 mg/dL. A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The Europen Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
Different Lp(a) levels can be found in different racial/ethnicity groups.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 3 mg/dL of initial values of samples ≤ 30 mg/dL and within ± 10 % for samples > 30 mg/dL.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference from rheumatoid factors up to a concentration of 1200 IU/mL.
Plasminogen: No significant cross‑reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross‑reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 190 mg/dL.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on cobas c systems. All special wash programming necessary for avoiding carry-over is available via the cobas link. The latest version of the carry-over evasion list can be found with the NaOHD/SMS/SCCS Method
| Analyzer(s) on which cobas c pack(s) can be used | ||
08106126190 | Tina‑quant Lipoprotein (a) Gen.2 (150 tests) | System‑ID 2086 001 | |
05852641160 | Preciset Lp(a) Gen.2 (5 × 1 mL) | Codes 20962‑20966 | |
05852650160 | PreciControl Lp(a) Gen.2 |
| |
08063494190 | Diluent NaCl 9 % (123 mL) | System‑ID 2906 001 |
LPA2X: ACN 20861
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
Reporting time | 10 min | ||
Wavelength (sub/main) | 800/660 nm | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 100 µL | – | |
R3 | 25 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 1.5 µL | – | – |
Decreased | 6.0 µL | 8 µL | 88 µL |
Increased | 1.5 µL | – | – |
For further information about the assay test definitions refer to the application parameters screen of the corresponding analyzer and assay.
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 26 weeks |
Calibrators | S1: H2O |
Calibration mode | Non-linear |
Calibration frequency | Automatic full calibration Full calibration |
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against an in-house reference material.
Representative performance data on the analyzers are given below. These data represent the performance of the analytical procedure itself.
Results obtained in individual laboratories may differ due to heterogenous sample materials, aging of analyzer components and mixture of reagents running on the analyzer.
Precision was determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP05‑A3 requirements with repeatability (n = 84) and intermediate precision (2 aliquots per run, 2 runs per day, 21 days).
Repeatability | Mean | SD | CV |
Lp (a) Control Level Low | 19.5 | 0.158 | 0.8 |
Lp (a) Control Level High | 47.2 | 0.197 | 0.4 |
Human serum 1 | 13.8 | 0.250 | 1.8 |
Human serum 2 | 38.1 | 0.170 | 0.4 |
Human serum 3 | 53.7 | 0.174 | 0.3 |
Human serum 4 | 65.6 | 0.216 | 0.3 |
Human serum 5 | 79.3 | 0.321 | 0.4 |
Intermediate precision | Mean | SD | CV |
Lp (a) Control Level Low | 19.5 | 0.219 | 1.1 |
Lp (a) Control Level High | 47.2 | 0.490 | 1.0 |
Human serum 1 | 13.8 | 0.286 | 2.1 |
Human serum 2 | 38.1 | 0.262 | 0.7 |
Human serum 3 | 53.7 | 0.355 | 0.7 |
Human serum 4 | 65.6 | 0.601 | 0.9 |
Human serum 5 | 79.3 | 0.620 | 0.8 |
Lipoprotein (a) values for human serum and plasma samples obtained on a cobas c 503 analyzer (y) were compared with those determined using the corresponding reagent on a cobas c 501 analyzer (x).
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.020x + 0.343 mg/dL | y = 1.013x + 0.537 mg/dL |
τ = 0.981 | r = 0.999 |
The sample concentrations were between 6.57 and 77.6 mg/dL.
Lipoprotein (a) values for human serum and plasma samples obtained on a cobas c 303 analyzer (y) were compared with those determined using the corresponding reagent on a cobas c 501 analyzer (x).
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.000x + 0.385 mg/dL | y = 0.990x + 0.788 mg/dL |
τ = 0.984 | r = 0.999 |
The sample concentrations were between 6.21 and 74.9 mg/dL.
Lipoprotein (a) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
The main problem for accurate detection of Lp(a) is the size polymorphism of apolipoprotein a (apo (a)). Levels of Lp(a) vary drastically among individuals and ethnic groups as the level is predominantly determined by the apo (a) gene on chromosome 6.
The high variable number of KRINGLE 4 type2 domains results in an apo (a) size ranging from 187 kDa to over 662 kDa.
High lipoprotein (a) concentrations in serum correlate with premature manifestation of atherosclerosis and strokes. Lipoprotein (a) should be determined together with total cholesterol, HDL‑cholesterol and LDL‑cholesterol as well as triglycerides when assessing the total arteriosclerotic risk.
According to the European Atherosclerosis Society Lp(a) measurement should be recommended in selected cases at high risk and in subjects with a family history of premature cardio vascular disease.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; stabilizers; BSA; rabbit serum 0.1 %, preservative |
R3 | Latex particles coated with polyclonal anti‑human lipoprotein (a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3, BSA; preservative |
R1 is in position B and R3 is in position C.
For in vitro diagnostic use.
Exercise the normal precautions required for handling all laboratory reagents.
Disposal of all waste material should be in accordance with local guidelines.
Safety data sheet available for professional user on request.
For USA: Caution: Federal law restricts this device to sale by or on the order of a physician.
For quality control, use control materials as listed in the \"Order information\" section.
In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. It is recommended to perform quality control always after lot calibration and subsequently at least every 26 weeks. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li‑heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
Plasma samples drawn with each of Li‑Heparin, K2‑, K3‑EDTA, serum and additionally gel separation tubes from 39 subjects were evaluated on a cobas c 501 system using the Roche Lp(a) Gen. 2 reagent and calibrators. Results of the comparison study showed that serum and plasma samples can provide substantially the same Lp(a) values.
Serum | Li- | K2- | K3- | Gel separation tubes | |
|---|---|---|---|---|---|
Median [mg/dL] | 27.2 | 27.5 | 27.2 | 27.0 | 27.5 |
Serum vs. plasma |
|
|
|
|
|
LCL 95 (Intercept) | - | ‑0.392 | ‑0.068 | ‑0.127 | ‑0.151 |
See the limitations and interferences section for details about possible sample interferences.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
If samples are not assayed within 48 h,
Sample stability claims were established by experimental data by the manufacturer or based on reference literature and only for the temperatures/time frames as stated in the method sheet. It is the responsibility of the individual laboratory to use all available references and/or its own studies to determine specific stability criteria for its laboratory.
In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on Roche/Hitachi cobas c systems.
Particle enhanced immunoturbidimetric assay.
Human lipoprotein (a) agglutinates with latex particles coated with anti‑Lp(a) antibodies. The precipitate is determined turbidimetrically at 800 / 660 nm.
Measuring range: 7‑240 nmol/L
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Limit of Blank | = 6 nmol/L |
Limit of Detection | = 7 nmol/L |
Limit of Quantitation | = 20 nmol/L |
The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 20 %. It has been determined using low concentration lipoprotein (a) samples.
A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The European Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
However the NHLBI recommends to stop using data for total Lp(a) mass, and to use nmol/L units instead, which consider the number of particles. Additionally they recommend to use assays independent from apo(a) size and standardized according to the IFCC reference material SRM2B.
Based on the evaluation of Framingham data values above 75 nmol/L are regarded as a cut‑off value for the presence of an increased risk.
Elevated Lp(a) levels can be found in most racial/ethnicity groups, with the prevalence being lowest in whites and Asians. The median Lp(a) levels in black subjects and in Asian Indians from southern locations are 2‑ to 4‑fold higher compared with whites, and up to 68 % of blacks have Lp(a) levels > 75 nmol/L, whereas levels above this threshold are present in around 25 % of whites.
Therefore reference ranges have not been established for this assay for different ethnic populations or disease states. Since Lp(a) levels are largely influenced by hereditary factors and vary with ethnic populations it is recommended that each laboratory establish own expected values.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 6 nmol/L of initial values of samples ≤ 60 nmol/L and within ± 10 % for samples > 60 nmol/L.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference from rheumatoid factors up to a concentration of 1200 IU/mL.
Plasminogen: No significant cross‑reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross‑reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 450 nmol/L.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on
|
| Analyzer(s) on which cobas c pack(s) can be used | |
08106126190 | Tina‑quant Lipoprotein (a) Gen.2 (150 tests) | System‑ID 2086 001 |
Materials required (but not provided):
05852641190 | Preciset Lp(a) Gen.2 (5 × 1 mL) | Codes 20962‑20966 | |
05852650190 | PreciControl Lp(a) Gen.2 |
| |
08063494190 | Diluent NaCl 9 % (123 mL) | System‑ID 2906 001 |
LPA2: ACN 20860
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
Reporting time | 10 min | ||
Wavelength (sub/main) | 800/660 nm | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 100 µL | – | |
R3 | 25 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 1.5 µL | – | – |
Decreased | 6.0 µL | 8 µL | 88 µL |
Increased | 1.5 µL | – | – |
For further information about the assay test definitions refer to the application parameters screen of the corresponding analyzer and assay.
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 26 weeks |
Calibrators | S1: H2O |
Calibration mode | Non-linear |
Calibration frequency | Automatic full calibration Full calibration |
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against the IFCC reference material SRM2B for nmol/L.
Representative performance data on the analyzers are given below. These data represent the performance of the analytical procedure itself.
Results obtained in individual laboratories may differ due to heterogenous sample materials, aging of analyzer components and mixture of reagents running on the analyzer.
Precision was determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP05‑A3 requirements with repeatability (n = 84) and intermediate precision (2 aliquots per run, 2 runs per day, 21 days).
Repeatability | Mean | SD | CV |
Lp (a) Control Level Low | 35.2 | 0.412 | 1.2 |
Lp (a) Control Level High | 97.7 | 0.435 | 0.4 |
Human serum 1 | 19.7 | 0.414 | 2.1 |
Human serum 2 | 49.3 | 0.516 | 1.0 |
Human serum 3 | 80.5 | 0.434 | 0.5 |
Human serum 4 | 120 | 0.546 | 0.5 |
Human serum 5 | 203 | 0.794 | 0.4 |
Intermediate precision | Mean | SD | CV |
Lp (a) Control Level Low | 35.1 | 0.562 | 1.6 |
Lp (a) Control Level High | 99.0 | 1.14 | 1.2 |
Human serum 1 | 19.7 | 0.508 | 2.6 |
Human serum 2 | 49.3 | 0.676 | 1.4 |
Human serum 3 | 80.5 | 0.831 | 1.0 |
Human serum 4 | 119 | 1.14 | 1.0 |
Human serum 5 | 203 | 1.33 | 0.7 |
Lipoprotein (a) values for human serum and plasma samples obtained on a cobas c 503 analyzer (y) were compared with those determined using the corresponding reagent on a cobas c 501 analyzer (x).
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.019x + 0.878 nmol/L | y = 1.010x + 1.34 nmol/L |
τ = 0.988 | r = 1.000 |
The sample concentrations were between 7.34 and 235 nmol/L.
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 0.984x + 2.00 nmol/L | y = 0.988x + 1.70 nmol/L |
τ = 0.990 | r = 1.000 |
The sample concentrations were between 7.07 and 222 nmol/L.
Lipoprotein (a) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
Main problem for accurate detection of Lp(a) is the size polymorphism of apolipoprotein a (apo (a)). Levels of Lp(a) vary drastically among individuals and ethnic groups as the level is predominantly determined by the apo (a) gene on chromosome 6.
The high variable number of KRINGLE 4 type2 domains results in an apo (a) size ranging from 187 kDa to over 662 kDa. Assays with antibodies directed against this variable part of the Lp(a) molecule will underestimate Lp(a) in patients with apo (a) smaller than in the used calibrator and overestimate Lp(a) in such samples with larger apo (a) particles as in the calibrator. Based on the size heterogeneity it makes no sense to measure Lp(a) mass. Therefore the values should be expressed in terms of nanomoles per liter of Lp(a) protein.
Only standardization of these assays against an apo (a) size independent method will yield correct results. Such methods use antibodies that recognize a single copy of apo (a) per particle. By using the WHO/IFCC International Reference Reagent (SRM2B) this goal can be reached.
According to the European Atherosclerosis Society Lp(a) measurement should be recommended in selected cases at high risk and in subjects with a family history of premature cardio vascular disease.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; stabilizers; BSA; rabbit serum 0.1 %, preservative |
R3 | Latex particles coated with polyclonal anti‑human lipoprotein(a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3, BSA; preservative |
R1 is in position B and R3 is in position C.
For in vitro diagnostic use for health care professionals. Exercise the normal precautions required for handling all laboratory reagents.
Infectious or microbial waste:
Warning: handle waste as potentially biohazardous material. Dispose of waste according to accepted laboratory instructions and procedures.
Environmental hazards:
Apply all relevant local disposal regulations to determine the safe disposal.
Safety data sheet available for professional user on request.
For quality control, use control materials as listed in the “Order information” section. In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. It is recommended to perform quality control always after lot calibration and subsequently at least every 26 weeks. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li‑heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
See the limitations and interferences section for details about possible sample interferences.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
If samples are not assayed within 48 h,
In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on Roche/Hitachi cobas c systems.
Particle enhanced immunoturbidimetric assay.
Measuring range
Measuring range: 7‑240 nmol/L
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Lower limits of measurement
Limit of Blank | = 6 nmol/L |
Limit of Detection | = 7 nmol/L |
Limit of Quantitation | = 20 nmol/L |
The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 30 %. It has been determined using low concentration Lp(a) samples.
A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The European Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
However the NHLBI recommends to stop using data for total Lp(a) mass, and to use nmol/L units instead, which consider the number of particles. Additionally they recommend to use assays independent from apo(a) size and standardized according to the IFCC reference material SRM2B.
Based on the evaluation of Framingham data values above 75 nmol/L are regarded as a cut‑off value for the presence of an increased risk.
Elevated Lp(a) levels can be found in most racial/ethnicity groups, with the prevalence being lowest in whites and Asians. The median Lp(a) levels in black subjects and in Asian Indians from southern locations are 2‑ to 4‑fold higher compared with whites, and up to 68 % of blacks have Lp(a) levels > 75 nmol/L, whereas levels above this threshold are present in around 25 % of whites.
Therefore reference ranges have not been established for this assay for different ethnic populations or disease states. Since Lp(a) levels are largely influenced by hereditary factors and vary with ethnic populations it is recommended that each laboratory establish own expected values.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 6 nmol/L of initial values of samples ≤ 60 nmol/L and within ± 10 % for samples > 60 nmol/L.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference up to a level of 1200 IU/mL.
Plasminogen: No significant cross‑reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross‑reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 450 nmol/L.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on cobas c systems. All special wash programming necessary for avoiding carry‑over is available via the cobas link, manual input is required in certain cases. The latest version of the carry‑over evasion list can be found with the NaOHD/SMS/SmpCln1+2/SCCS Method Sheet and for further instructions refer to the operator’s manual.
Where required, special wash/carry‑over evasion programming must be implemented prior to reporting results with this test.
|
| Analyzer(s) on which cobas c pack(s) can be used | |
05852633 190 | Tina-quant Lipoprotein (a) Gen.2 (200 tests) | System‑ID 03 7504 5 | cobas c 701/702 |
Materials required (but not provided):
05852641 190 | Preciset Lp(a) Gen.2 ( | Codes 962-966 | |
05852650 190 | PreciControl Lp(a) Gen.2 (Level Low | Code 137 | |
05172152 190 | Diluent NaCL 9 % (119 mL) | System‑ID 08 6869 3 |
LPA2: ACN 8723.
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
cobas c 701/702 test definition | |||
Assay type | 2‑Point End | ||
Reaction time / Assay points | 10 / 22‑33 | ||
Wavelength (sub/main) | 800 / 660 nm | ||
Reaction direction | Increase | ||
Unit | nmol/L | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 133 µL | – | |
R3 | 33 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 2.0 µL | 0 µL | 0 µL |
Decreased | 8.0 µL | 10 µL | 110 µL |
Increased | 4.0 µL | 0 µL | 0 µL |
LPA2 | |
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 6 weeks |
On‑board on the Reagent Manager: | 24 hours |
Diluent NaCl 9 % | |
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 4 weeks |
On‑board on the Reagent Manager: | 24 hours |
Calibrators | S1: H2O |
Calibration mode | Spline |
Calibration frequency | Full calibration |
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against the IFCC reference material SRM2B for nmol/L.
Representative performance data on the analyzers are given below. Results obtained in individual laboratories may differ.
Repeatability was determined using human samples and controls in an internal protocol (n = 21, 1 run). Intermediate precision was determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP5 requirements (2 aliquots per run, 2 runs per day, 21 days). The following results were obtained:
Repeatability | |||
|---|---|---|---|
Sample | Mean | SD | CV |
Lp (a) Control level L | 41.7 | 0.5 | 1.2 |
Lp (a) Control level H | 167 | 1 | 0.7 |
Human serum 4 | 24.6 | 0.4 | 1.7 |
Human serum 5 | 66.4 | 1.6 | 2.4 |
Human serum 7 | 233 | 1 | 0.6 |
Intermediate precision | |||
|---|---|---|---|
Sample | Mean | SD | CV |
Lp (a) Control level L | 40.7 | 0.7 | 1.7 |
Lp (a) Control level H | 156 | 2 | 1.2 |
Human serum 1 | 18.2 | 1.5 | 8.0 |
Human serum 2 | 88.7 | 2.7 | 3.0 |
Human serum 3 | 226 | 2 | 1.1 |
Results for intermediate precision were obtained on the master system cobas c 501 analyzer.
Lipoprotein (a) values for human serum and plasma samples obtained on a
Sample size (n) = 163
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.00x + 0.000 nmol/L | y = 0.998x - 0.098 nmol/L |
τ = 0.977 | r = 1.00 |
The sample concentrations were between 7.10 and 233 nmol/L.
Lipoprotein (a) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
Main problem for accurate detection of Lp(a) is the size polymorphism of apolipoprotein a (apo (a)). Levels of Lp(a) vary drastically among individuals and ethnic groups as the level is predominantly determined by the apo (a) gene on chromosome 6.
The high variable number of KRINGLE 4 type2 domains results in an apo (a) size ranging from 187 kDa to over 662 kDa. Assays with antibodies directed against this variable part of the Lp(a) molecule will underestimate Lp(a) in patients with apo (a) smaller than in the used calibrator and overestimate Lp(a) in such samples with larger apo (a) particles as in the calibrator. Based on the size heterogeneity it makes no sense to measure Lp(a) mass. Therefore the values should be expressed in terms of nanomoles per liter of Lp(a) protein.
Only standardization of these assays against an apo (a) size independent method will yield correct results. Such methods use antibodies that recognize a single copy of apo (a) per particle. By using the WHO/IFCC International Reference Reagent (SRM2B) this goal can be reached.
According to the European Atherosclerosis Society Lp(a) measurement should be recommended in selected cases at high risk and in subjects with a family history of premature cardio vascular disease.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; stabilizers; BSA; rabbit serum 0.1 %, preservative |
R3 | Latex particles coated with polyclonal anti‑human lipoprotein(a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3, BSA; preservative |
R1 is in position B and R3 is in position C.
For in vitro diagnostic use for health care professionals. Exercise the normal precautions required for handling all laboratory reagents.
Infectious or microbial waste:
Warning: handle waste as potentially biohazardous material. Dispose of waste according to accepted laboratory instructions and procedures.
Environmental hazards:
Apply all relevant local disposal regulations to determine the safe disposal.
Safety data sheet available for professional user on request.
For quality control, use control materials as listed in the \"Order information\" section.
In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li‑heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
See the limitations and interferences section for details about possible sample interferences.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
If samples are not assayed within 48 h,
In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on COBAS INTEGRA systems.
Particle-enhanced immunoturbidimetric assay
Human lipoprotein (a) agglutinates with latex particles coated with anti-Lp(a) antibodies. The precipitate is determined turbidimetrically at 659 nm.
7-240 nmol/L
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Limit of Blank, Limit of Detection and Limit of Quantitation
Limit of Blank | = 6 nmol/L |
Limit of Detection | = 7 nmol/L |
Limit of Quantitation | = 20 nmol/L |
The Limit of Blank, the Limit of Detection and the Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 30 %. It has been determined using low concentration Lp(a) samples.
A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The European Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
However the NHLBI recommends to stop using data for total Lp(a) mass, and to use nmol/L units instead, which consider the number of particles. Additionally they recommend to use assays independent from apo(a) size and standardized according to the IFCC reference material SRM2B.
Based on the evaluation of Framingham data values above 75 nmol/L are regarded as a cut-off value for the presence of an increased risk.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 6 nmol/L of initial values of samples ≤ 60 nmol/L and within ± 10 % for samples > 60 nmol/L.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference up to a rheumatoid factors level of 1200 IU/mL.
Plasminogen: No significant cross reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 450 nmol/L.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on COBAS INTEGRA analyzers. Refer to the CLEAN Method Sheet for further instructions and for the latest version of the Extra wash cycle list.
Where required, special wash/carry-over evasion programming must be implemented prior to reporting results with this test.
|
| Analyzers on which cobas c pack(s) can be used | |
05852625 190 | Tina-quant Lipoprotein (a) Gen.2 (150 tests) | System-ID 07 7504 5 | COBAS INTEGRA 400 plus |
Materials required (but not provided):
05852641 190 | Preciset Lp(a) Gen.2 (5 × 1 mL) | System-ID 07 7546 0 | |
05852650 190 | PreciControl Lp(a) Gen.2 |
| |
20756350 322 | NaCl Diluent 9 % (6 × 22 mL) | System-ID 07 5635 0 |
Test LPA2, test ID 0‑039
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
Measuring mode | Absorbance |
Abs. calculation mode | Endpoint |
Reaction mode | D-R1-S-SR |
Reaction direction | Increase |
Wavelength A/B | 659 nm |
Calc. first/last | 36-53 |
Typical prozone effect | > 450 nmol/L |
Antigen excess check | No |
Predilution factor | 11 |
Unit | nmol/L |
Diluent (H2O) | ||
R1 | 133 µL | |
SR | 33 µL | 5 µL |
Sample | 20 µL | |
191 µL |
Shelf life at 2‑8 °C | See expiration date on cobas c pack label |
6 weeks |
Calibrator | Preciset Lp(a) Gen. 2 Use deionized water as zero calibrator. |
Calibration mode | Spline |
Calibration replicate | Duplicate recommended |
Calibration interval | Each lot and as required following quality control procedures |
Calibrators must be placed from the highest concentration first, to the lowest last, on the CAL/QC rack. 0 nmol/L calibrator is not provided with Preciset Lp(a) Gen.2. Please use deionized water as zero calibrator.
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against the IFCC reference material SRM2B for nmol/L.
Representative performance data on the analyzers are given below. Results obtained in individual laboratories may differ.
Repeatability and intermediate precision were determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP5 requirements (2 aliquots per run, 2 runs per day, 21 days). The following results were obtained:
Repeatability | Mean | SD | CV |
|---|---|---|---|
PreciControl Level L | 37.0 | 0.5 | 1.3 |
PreciControl Level H | 136 | 1 | 0.6 |
Human serum 1 | 16.7 | 0.6 | 3.7 |
Human serum 3 | 86.3 | 0.5 | 0.6 |
Human serum 5 | 205 | 1 | 0.4 |
Intermediate precision | Mean | SD | CV |
|---|---|---|---|
PreciControl Level L | 37.0 | 0.5 | 1.4 |
PreciControl Level H | 136 | 1 | 0.7 |
Human serum 1 | 16.7 | 0.6 | 3.8 |
Human serum 3 | 86.3 | 1.0 | 1.1 |
Human serum 5 | 205 | 1 | 0.6 |
Lipoprotein (a) values for human serum and plasma samples obtained on a COBAS INTEGRA 800 analyzer (y) were compared with those determined using the corresponding reagent on a cobas c 501 analyzer (x).
Sample size (n) = 240 | |
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.02x + 0.290 nmol/L | y = 1.01x + 0.972 nmol/L |
τ = 0.938 | r = 0.999 |
The sample concentrations were between 7.11 and 234 nmol/L.
Lipoprotein (a) values for human serum and plasma samples obtained on a COBAS INTEGRA 800 analyzer (y) were compared with those determined using the Northwest Lipid Metabolism and Diabetes Research Laboratories ELISA method traceable to the WHO/IFCC reference material SRM2B (x).
Sample size (n) = 105 | |
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 1.01x + 1.92 nmol/L | y = 0.975x + 3.13 nmol/L |
τ = 0.939 | r = 0.993 |
The sample concentrations were between 7.10 and 218 nmol/L.
Lipoprotein (a) (Lp(a)) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
Assays with antibodies directed against this variable part of the Lp(a) molecule will underestimate Lp(a) in patients with apo (a) smaller than in the used calibrator and overestimate Lp(a) in such samples with larger apo (a) particles as in the calibrator. Based on the size heterogeneity it makes no sense to measure Lp(a) mass. Therefore the values should be expressed in terms of nanomoles per liter of Lp(a) protein.
Only standardization of these assays against an apo (a) size independent method will yield correct results. Such methods use antibodies that recognize a single copy of apo (a) per particle. By using the WHO/IFCC International Reference Reagent (SRM2B) this goal can be reached.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; BSA; rabbit serum 0.1 %; stabilizers; preservative |
SR | Latex particles coated with polyclonal anti‑human lipoprotein (a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3; BSA; preservative |
R1 is in position B and SR is in position C.
For in vitro diagnostic use for health care professionals. Exercise the normal precautions required for handling all laboratory reagents.
Infectious or microbial waste:
Warning: handle waste as potentially biohazardous material. Dispose of waste according to accepted laboratory instructions and procedures.
Environmental hazards:
Apply all relevant local disposal regulations to determine the safe disposal.
Safety data sheet available for professional user on request.
Quality control | PreciControl Lp(a) Gen. 2 |
Control interval | 24 hours recommended |
Control sequence | User defined |
Control after calibration | Recommended |
For quality control, use control materials as listed in the “Order information” section. In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li-heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
See the limitations and interferences section for details about possible sample interferences.
Samples and controls are automatically prediluted 1:11 (1 + 10) with NaCl solution by the instrument.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
In vitro test for the quantitative determination of lipoprotein (a) in human serum and plasma on Roche/Hitachi cobas c systems.
Particle enhanced immunoturbidimetric assay.
Measuring range
Measuring range: 7‑240 nmol/L
Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:3 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 3.
Lower limits of measurement
Limit of Blank | = 6 nmol/L |
Limit of Detection | = 7 nmol/L |
Limit of Quantitation | = 20 nmol/L |
The Limit of Blank, Limit of Detection and Limit of Quantitation were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17‑A2 requirements.
The Limit of Blank is the 95th percentile value from n ≥ 60 measurements of analyte‑free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte‑free samples are found with a probability of 95 %.
The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.
The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).
The Limit of Quantitation is the lowest analyte concentration that can be reproducibly measured with a total error of 30 %. It has been determined using low concentration Lp(a) samples.
A Lp(a) concentration of 30 mg/dL corresponding to the 75th percentile in a male Caucasian reference population is widely used as cut‑off point or threshold value.
The European Atherosclerosis Society recommends screening for elevated Lp(a) in those at intermediate or high CVD/CHD risk and defines a desirable Lp(a) level ≤ 50 mg/dL.
However the NHLBI recommends to stop using data for total Lp(a) mass, and to use nmol/L units instead, which consider the number of particles. Additionally they recommend to use assays independent from apo(a) size and standardized according to the IFCC reference material SRM2B.
Based on the evaluation of Framingham data values above 75 nmol/L are regarded as a cut‑off value for the presence of an increased risk.
Elevated Lp(a) levels can be found in most racial/ethnicity groups, with the prevalence being lowest in whites and Asians. The median Lp(a) levels in black subjects and in Asian Indians from southern locations are 2‑ to 4‑fold higher compared with whites, and up to 68 % of blacks have Lp(a) levels > 75 nmol/L, whereas levels above this threshold are present in around 25 % of whites.
Therefore reference ranges have not been established for this assay for different ethnic populations or disease states. Since Lp(a) levels are largely influenced by hereditary factors and vary with ethnic populations it is recommended that each laboratory establish own expected values.
Each laboratory should investigate the transferability of the expected values to its own patient population and if necessary determine its own reference ranges.
Criterion: Recovery within ± 6 nmol/L of initial values of samples ≤ 60 nmol/L and within ± 10 % for samples > 60 nmol/L.
Icterus:
Hemolysis:
Lipemia (Intralipid):
Rheumatoid factors: No significant interference up to a level of 1200 IU/mL.
Plasminogen: No significant cross‑reactivity in the tested concentration range (up to 150 mg/dL).
Apolipoprotein B: No significant cross‑reactivity in the tested concentration range (up to 200 mg/dL).
Drugs: No interference was found at therapeutic concentrations using common drug panels.
High dose hook‑effect: No false result occurs up to a lipoprotein (a) concentration of 450 nmol/L.
In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.
For diagnostic purposes, the results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.
ACTION REQUIRED
Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on cobas c systems. The latest version of the carry‑over evasion list can be found with the NaOHD-SMS-SmpCln1+2-SCCS Method Sheets. For further instructions refer to the operator’s manual. cobas c 502 analyzer: All special wash programming necessary for avoiding carry‑over is available via the cobas link, manual input is required in certain cases.
Where required, special wash/carry‑over evasion programming must be implemented prior to reporting results with this test.
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| Analyzer(s) on which cobas c pack(s) can be used | |
05852625 190 | Tina‑quant Lipoprotein (a) Gen.2 (150 tests) | System‑ID 07 7504 5 | cobas c 311, cobas c 501/502 |
Materials required (but not provided):
05852641 190 | Preciset Lp(a) Gen.2 ( | Codes 962‑966 | |
05852650 190 | PreciControl Lp(a) Gen.2 (Level Low | Code 137 | |
04489357 190 | Diluent NaCl 9 % (50 mL) | System‑ID 07 6869 3 |
For cobas c 311/501 analyzers:
LPA2: ACN 723
For cobas c 502 analyzer:
LPA2: ACN 8723
Ready for use
Carefully invert reagent container several times prior to use to ensure that the reagent components are mixed.
cobas c 311 test definition | |||
Assay type | 2‑Point End | ||
Reaction time / Assay points | 10 / 26‑49 | ||
Wavelength (sub/main) | 800 / 660 nm | ||
Reaction direction | Increase | ||
Unit | nmol/L | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 133 µL | – | |
R3 | 33 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 2.0 µL | 0 µL | 0 µL |
Decreased | 8.0 µL | 10 µL | 110 µL |
Increased | 2.0 µL | 0 µL | 0 µL |
cobas c 501 test definition | |||
Assay type | 2‑Point End | ||
Reaction time / Assay points | 10 / 40‑60 | ||
Wavelength (sub/main) | 800 / 660 nm | ||
Reaction direction | Increase | ||
Unit | nmol/L | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 133 µL | – | |
R3 | 33 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 2.0 µL | 0 µL | 0 µL |
Decreased | 8.0 µL | 10 µL | 110 µL |
Increased | 2.0 µL | 0 µL | 0 µL |
cobas c 502 test definition | |||
Assay type | 2‑Point End | ||
Reaction time / Assay points | 10 / 40‑60 | ||
Wavelength (sub/main) | 800 / 660 nm | ||
Reaction direction | Increase | ||
Unit | nmol/L | ||
Reagent pipetting | Diluent (H2O) | ||
R1 | 133 µL | – | |
R3 | 33 µL | – | |
Sample volumes | Sample | Sample dilution | |
Sample | Diluent (NaCl) | ||
Normal | 2.0 µL | 0 µL | 0 µL |
Decreased | 8.0 µL | 10 µL | 110 µL |
Increased | 4.0 µL | 0 µL | 0 µL |
LPA2 | |
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 6 weeks |
Diluent NaCl 9 % | |
Shelf life at 2‑8 °C: | See expiration date on cobas c pack label. |
On‑board in use and refrigerated on the analyzer: | 12 weeks |
Calibrators | S1: H2O |
Calibration mode | Spline |
Calibration frequency | Full calibration |
Calibration interval may be extended based on acceptable verification of calibration by the laboratory.
Traceability: This method has been standardized against the IFCC reference material SRM2B for nmol/L.
Representative performance data on the analyzers are given below. Results obtained in individual laboratories may differ.
Repeatability and intermediate precision were determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP5 requirements (2 aliquots per run, 2 runs per day, 21 days). The following results were obtained:
Repeatability | |||
|---|---|---|---|
Sample | Mean | SD | CV |
Lp (a) Control level L | 40.7 | 0.6 | 1.5 |
Lp (a) Control level H | 156 | 2 | 1.1 |
Human serum 1 | 18.2 | 1.0 | 5.6 |
Human serum 2 | 88.7 | 2.2 | 2.5 |
Human serum 3 | 226 | 2 | 0.8 |
Intermediate precision | |||
|---|---|---|---|
Sample | Mean | SD | CV |
Lp (a) Control level L | 40.7 | 0.7 | 1.7 |
Lp (a) Control level H | 156 | 2 | 1.2 |
Human serum 1 | 18.2 | 1.5 | 8.0 |
Human serum 2 | 88.7 | 2.7 | 3.0 |
Human serum 3 | 226 | 2 | 1.1 |
Lipoprotein (a) values for human serum and plasma samples obtained on a
Sample size (n) = 240
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 0.980x - 0.285 nmol/L | y = 0.985x - 0.745 nmol/L |
τ = 0.938 | r = 0.999 |
The sample concentrations were between 7.61 and 234 nmol/L.
Lipoprotein (a) values for human serum and plasma samples obtained on a
Sample size (n) = 105
Passing/Bablok LREFBablok W, Passing H, Bender R, et al. A general regression procedure for method transformation. Application of linear regression procedures for method comparison studies in clinical chemistry, Part III. J Clin Chem Clin Biochem 1988 Nov;26(11):783-790. | Linear regression |
y = 0.935x + 0.606 nmol/L | y = 0.942x + 0.105 nmol/L |
τ = 0.947 | r = 0.995 |
The sample concentrations were between 7.10 and 218 nmol/L.
Lipoprotein (a) is composed of an LDL‑like particle to which the lipoprotein (a)‑specific apolipoprotein (a) is bonded by a disulfide bridge. Apolipoprotein (a) is highly homologous to plasminogen. Lipoprotein (a) is a cholesterol‑rich lipoprotein which is synthesized in the liver independently of triglycerides and is not subject to the influence of age or diet.
Several unrelated studies showed that Lp(a) is an independent prospective risk factor for coronary heart disease. However acceptance is limited due to the fact that it is difficult to compare Lp(a) results between different clinical studies and the assays used showed strong variations and miscellaneous standardization levels.
Main problem for accurate detection of Lp(a) is the size polymorphism of apolipoprotein a (apo (a)). Levels of Lp(a) vary drastically among individuals and ethnic groups as the level is predominantly determined by the apo (a) gene on chromosome 6.
The high variable number of KRINGLE 4 type2 domains results in an apo (a) size ranging from 187 kDa to over 662 kDa. Assays with antibodies directed against this variable part of the Lp(a) molecule will underestimate Lp(a) in patients with apo (a) smaller than in the used calibrator and overestimate Lp(a) in such samples with larger apo (a) particles as in the calibrator. Based on the size heterogeneity it makes no sense to measure Lp(a) mass. Therefore the values should be expressed in terms of nanomoles per liter of Lp(a) protein.
Only standardization of these assays against an apo (a) size independent method will yield correct results. Such methods use antibodies that recognize a single copy of apo (a) per particle. By using the WHO/IFCC International Reference Reagent (SRM2B) this goal can be reached.
According to the European Atherosclerosis Society Lp(a) measurement should be recommended in selected cases at high risk and in subjects with a family history of premature cardio vascular disease.
R1 | Glycine buffer: 170 mmol/L, pH 7.0; stabilizers; BSA; rabbit serum 0.1 %, preservative |
R3 | Latex particles coated with polyclonal anti‑human lipoprotein(a) antibodies (rabbit); glycine buffer: 170 mmol/L, pH 7.3, BSA; preservative |
R1 is in position B and R3 is in position C.
For in vitro diagnostic use for health care professionals. Exercise the normal precautions required for handling all laboratory reagents.
Infectious or microbial waste:
Warning: handle waste as potentially biohazardous material. Dispose of waste according to accepted laboratory instructions and procedures.
Environmental hazards:
Apply all relevant local disposal regulations to determine the safe disposal.
Safety data sheet available for professional user on request.
For quality control, use control materials as listed in the \"Order information\" section.
In addition, other suitable control material can be used.
The control intervals and limits should be adapted to each laboratory’s individual requirements. Values obtained should fall within the defined limits. Each laboratory should establish corrective measures to be taken if values fall outside the defined limits.
Follow the applicable government regulations and local guidelines for quality control.
For specimen collection and preparation only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Serum
Plasma: Li‑heparin or K2‑EDTA and K3‑EDTA plasma.
The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, i.e. not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
With K3‑EDTA tubes pay particular attention that the tubes are adequately filled.
Centrifuge samples containing precipitates before performing the assay.
See the limitations and interferences section for details about possible sample interferences.
Stability:
If samples are not assayed within 8 hours, samples should be stored at 2‑8 °C.
If samples are not assayed within 48 h,
Tina-quant Lipoprotein (a) Gen.2
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