Novel Automated Immune Turbidimetric Assay for Routine Urinary Cystatin-C Determinations

Abstract

Aim: There is no commercially available urinary cystatin-C (u-CYSC) test in the market. Therefore, we optimized and validated an automated immune turbidimetric test for u-CYSC measurements and investigated u-CYSC concentrations in acute and chronic diseases which might lead to renal tubular disorders. Materials & methods: A particle-enhanced immune turbidimetric assay was adapted and validated on a Cobas 8000/c502 analyzer. Urine samples of different patient groups were also analyzed. Results: Our method showed excellent analytical performance. U-CYSC/u-creatinine (u-CREAT) was higher in sepsis-related acute kidney injury group (p < 0.001) compared with controls and to patients with chronic hypertension and Type 2 diabetes. Conclusion: We validated a fast, sensitive, fully automated u-CYSC assay which is ideal for routine use and might be a potential complementary laboratory test to evaluate renal tubular function.

Cystatin C Is a More Reliable Biomarker for Determining eGFR to Support Drug Development Studies

“…Another study of approximately 1500 children and adults after cardiac surgery also found no association of cystatin C with AKI . Further investigation of cystatin C in larger population studies is necessary to determine its value as a biomarker for AKI, and the recent development of validated, sensitive, and automated assays to measure urine cystatin C may help with this effort . Currently, however, cystatin C is not validated as a diagnostic biomarker for AKI.…”

Elevated urinary orosomucoid excretion as a novel biomarker in Crohn’s disease

“…Additionally, u‐ORM/u‐TP and u‐ALB/u‐TP ratios were also determined to examine the proportional change of ORM and albumin among urinary proteins. To check renal glomerular and tubular function, cystatin‐c was measured from serum samples by a commercial kit (Roche, Diagnostics GmbH) and from urine by our recently described automated turbidimetric assay …”

“…Renal function (glomerular and tubular) was normal in each group based on serum and urinary cystatin‐c (u‐CYSC) measurements. U‐CYSC/u‐CREAT showed difference only between adult control and active CD groups; however, all patients had u‐CYSC/u‐CREAT values within the reported reference range …”

“…U-CYSC/u-CREAT showed difference only between adult control and active CD groups; however, all patients had u-CYSC/u-CREAT values within the reported reference range. 23 The grade of inflammation was estimated by the conventional inflammatory parameters (hs-CRP, ESR, WBC, PLT, se-ORM) and by u-ORM/u-CREAT as well among our patient groups. Se-ORM was also increased in the active CD group compared to inactive patients (P < 0.001); however, its proportional increase was milder than that of u-ORM/u-CREAT particularly in children.…”

“…To check renal glomerular and tubular function, cystatin-c was measured from serum samples by a commercial kit (Roche, Diagnostics GmbH) and from urine by our recently described automated turbidimetric assay. 23…”