Elecsys® Anti-SARS-CoV-2

Immunoassay for the qualitative detection of antibodies (incl. IgG) against SARS-CoV-2

Elecsys pack

Immunoassay to qualitatively detect antibodies (including IgG) against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Elecsys® Anti-SARS-CoV-2 is an immunoassay for the in vitro qualitative detection of antibodies (including IgG) to SARS-CoV-2 in human serum and plasma. The test is intended as an aid in the determination of the immune reaction to SARS-CoV-2.

The electrochemiluminescence immunoassay “ECLIA” is intended for use on cobas e immunoassay analysers.  The assay uses a recombinant protein representing the nucleocapsid (N) antigen for the determination of antibodies against SARS-CoV-2. 

Elecsys® Anti-SARS-CoV-2 Factsheet


SARS-CoV-2: An overview of virus structure, transmission and detection


SARS-CoV-2 is an enveloped, single-stranded RNA virus of the family Coronaviridae. Coronaviruses share structural similarities and are composed of 16 nonstructural proteins and 4 structural proteins: spike, envelope, membrane, and nucleocapsid. Coronaviruses cause diseases with symptoms ranging from those of a mild common cold to more severe ones such as Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2.1,2

SARS-CoV-2 is transmitted from person-to-person primarily via respiratory droplets, while indirect transmission through contaminated surfaces is also possible.3-6 The virus accesses host cells via the angiotensin-converting enzyme 2 (ACE2), which is most abundant in the lungs.7-9

The incubation period for COVID-19 ranges from 2 – 14 days following exposure, with most cases showing symptoms approximately 4 – 5 days after exposure.3,10 The spectrum of symptomatic infection ranges from mild (fever, cough, fatigue, loss of smell, shortness of breath) to critical.11,12 While most symptomatic cases are not severe, severe illness occurs predominantly in adults with advanced age or underlying medical comorbidities and requires intensive care. Acute respiratory distress syndrome (ARDS) is a major complication in patients with severe disease. Critical cases are characterised, for example, by respiratory failure, shock and/or multiple organ dysfunction, or failure.11,13,14

Definitive COVID-19 diagnosis entails direct SARS-CoV-2 detection by nucleic acid amplification technology (NAAT).15-17 Serological assays can contribute to the identification of individuals exposed to the virus and assess the extent of exposure of a population, and might thereby help to decide on application, enforcement or relaxation of containment measures.18



Structure of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)


  • Nucleocapsid protein (N)
  • Envelope protein (E)
  • Spike protein (S)
  • Membrane glycoprotein (M)
  • RNA
Coronavirus illustration

Illustrative course of markers in SARS-CoV-2 infection19-27

Illustrative course of markers in SARS-CoV-2 infection

Elecsys® Anti-SARS-CoV-2

  • Systems

    cobas e 411 analyzer, cobas e 601 / cobas e 602 modules, cobas e 801 module

  • Testing time

    18 minutes

  • Calibration


  • Interpretation

    COI* < 1.0 = non-reactive
    COI ≥ 1.0 = reactive

  • Sample material

    Serum collected using standard sampling tubes. Li-heparin, K2-EDTA and K3-EDTA plasma.

  • Sample volume

    20 μL cobas e 411 analyzer, cobas e 601 / cobas e 602 modules
    12 μL cobas e 801 module

  • Onboard stability

    72 hours

* COI: cutoff index

Clinical specificity28

View Full Table

Clinical specificity28

A total of 5,272 samples (from diagnostic routine, blood donors, a common cold panel, and a coronavirus panel*) obtained before December 2019 were tested with the Elecsys® Anti-SARS-CoV-2 assay.

Cohort Sample number (N) Reactive Specificity % (95 % CI*)
Diagnostic routine 3420 7 99.80 % (99.58 – 99.92 %)
Blood donors 1772 3 99.83 % (99.51 – 99.97 %)
Common cold panel 40 0 100 % (91.19 – 100 %)
Coronavirus panel 40 0 100 % (91.19 – 100 %)
Overall 5272 10 99.81 % (99.65 – 99.91 %)
* 40 potentially cross-reactive samples from individuals with past infection with coronavirus HKU1, NL63, 229E, or OC43, confirmed by PCR.

Clinical sensitivity28

View Full Table

Clinical sensitivity28

A total of 204 samples from 69 symptomatic patients with a PCR confirmed SARS-CoV-2 infection were tested with the Elecsys® Anti-SARS-CoV-2 assay. One or more consecutive specimens from these patients were collected after PCR confirmation at various time points.

Days post PCR confirmation Sample number (N) Sensitivity (95 % CI)
0 – 6 days 116 65.5 % (56.1 – 74.1 %)
7 – 13 days 59 88.1 % (77.1 – 95.1 %)
≥14 days 29 100 % (88.1 – 100 %)
* CI: confidence interval
Seroconversion sensitivity28

After recovery from infection, confirmed by a negative PCR result, 26 consecutive samples from 5 individuals were tested with the Elecsys® Anti-SARS-CoV-2 assay.

Seroconversion sensitivity

* Day 0 represents initial positive PCR

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  28. Elecsys® Anti-SARS-CoV-2. Package Insert 2020-04, V1.0; Material Numbers 09203095190 and 09203079190