Supporting the early detection of chronic kidney disease
Chronic kidney disease (CKD) is an insidious disease with a dramatically increasing prevalence across the globe accompanied by a huge impact on healthcare budgets.1 Detecting chronic kidney disease at early stages allows for early intervention and thus has the potential to delay or even prevent the development of end-stage renal disease (ESRD) and related complications.2 Cystatin C is a marker with the ability to detect mild kidneyinsufficiency through subtle changes in the glomerular filtration rate (GFR).3 Therefore, cystatin C offers additional medical value versus the use of creatinine contributing to better patient cares.
Serum creatinine levels only begin to rise in CKD stage 3 when approximately 50 % of renal function is already lost (“creatinine-blind area”). Subtle changes in the GFR in CKD stages 1 and 2 – not detectable by creatinine-based measurements – can be determined by cystatin C due to its higher sensitivity and specificity.
Figure 1: Stages of chronic kidney disease according to NKF KDOQI4
Cystatin C is not affected by any physical factors such as muscle mass, age, gender or ethnicity. As a result, cystatin C shows a relatively high diagnostic sensitivity and specificity compared with creatinine, making it a reliable early marker of renal dysfunction. In a study of 93,000 patients, cystatin C-based estimation of GFR, correctly reclassified 42 % of patients with a creatinine-based estimation of GFR of 45 - 59 mL/min/1.73 to a “normal” risk group concerning end-stage renal disease and cardiovascular death.5
Figure 2: ROC analysis of cystatin C and creatinine3
Figure 3: Correlation between cobas c 501 and Siemens BN II cystatin C application. Highly developed turbidimetric detection technology delivers accurate results comparable to nephelometric measurement methods.6
