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Updated: Aug 25, 2026

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Published on: February 9, 2021
Measurement of urinary cystatin C by particle-enhanced nephelometric immunoassay: precision, interferences, stability
Stefan Herget-Rosenthal1, Thorsten Feldkamp, Lothar Volbracht
1Department of Nephrology, University Hospital, D-45122 Essen, Germany. herget.rosenthal@t-online.de
Background:
Urinary excretion of the low molecular weight protein cystatin C is a marker of renal disorders and a good predictor of the severity of acute tubular necrosis. We evaluated the measurement of urinary cystatin C and determined its reference range.
Methods:
Measurement of urinary cystatin C by particle-enhanced nephelometric immunoassay (PENIA) in 102 patients with various renal disorders and 133 healthy controls. We assessed the influence of pH and temperature, interferences on urinary cystatin C measurement, as well as cystatin C adsorption to plastic.
Results:
The upper reference value for urinary cystatin C was 0.28 mg/L, independent of age and gender. Accuracy and linearity (r(2)=0.996) were excellent. Intra- and inter-assay precision were < or =4.8% and < or =5.2%, respectively. Albumin (< or =160 g/L), bilirubin (< or =500 micromol/L) and haemoglobin (< or =210 micromol/L) did not show interferences. Urinary cystatin C was stable, at urine pH> or =5, at -20 degrees C and 4 degrees C for 7 days, and at 20 degrees C for 48 h. Freezing and thawing did not influence urinary cystatin C concentration. There was no adsorption of cystatin C to plastic.
Conclusion:
Urinary cystatin C measurement by PENIA is precise. High stability and no interference add to the practicability of urinary cystatin C as a routine biochemical test.
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