Serum cystatin C, determined by a rapid, automated particle-enhanced turbidimetric method, is a better marker than serum creatinine for glomerular filtration rate.
We describe a fully automated particle-enhanced turbidimetric assay for cystatin C in undiluted serum and EDTA-plasma. The throughput is 90 samples per hour and urgent samples can be analyzed in 7 min. The assay range (0.4-14.1 mg/L) covers the concentration range in health and disease. The within- and between-run imprecision is 0.9% and 2.2%, respectively. Analytical recovery of additions of recombinant cystatin C averaged 98%. Rheumatoid factors (< or = 323,000 IU/L), bilirubin (< or = 150 mumol/L), hemoglobin (< or = 1.2 g/L), and triglycerides (< or = 8.5 mmol/L) do not interfere in the assay. In view of the superior (by ROC analysis) diagnostic accuracy of serum concentrations of cystatin C for reduced glomerular filtration rate (GFR) in comparison with creatinine, cystatin C seems an attractive alternative to creatinine for estimation of GFR.
Kyhse-Andersen
J
J
Dako A/S, Glostrup, Denmark.
Schmidt
C
C
Nordin
G
G
Andersson
B
B
Nilsson-Ehle
P
P
Lindström
V
V
Grubb
A
A
D001322:Autoanalysis; D001663:Bilirubin / Q000097:blood; D015415:Biomarkers; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D004355:Drug Stability; D004492:Edetic Acid; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007118:Immunoassay; D008863:Microspheres; D009391:Nephelometry and Turbidimetry / Q000379:methods* / Q000706:statistics & numerical data; D012016:Reference Values; D012217:Rheumatoid Factor / Q000097:blood; D012680:Sensitivity and Specificity; D014280:Triglycerides / Q000097:blood
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D006454:Hemoglobins; D014280:Triglycerides; D012217:Rheumatoid Factor; D004492:Edetic Acid; D003404:Creatinine; D001663:Bilirubin