Human cystatin c elisa kit

Human cystatin C concentration in the plasma samples of the participants on ART was measured using the Human Cystatin C ELISA Kit (Cat# RD191009100, BioVendor, Brno, Czech Republic) as per the manufacturer’s instructions. Briefly, standards, quality control materials, and samples were first incubated in microtiter plates pre-coated with capture antibody. A secondary antibody conjugated with enzyme was added to the wells and incubated with the captured cystatin C after the recommended incubation and washing steps. Subsequently, the color was developed by the addition of substrate and stop solutions. A standard curve (four parameters) was constructed to determine the concentration of unknown samples. The sensitivity of the assay was 0.25 ng/mL.

Vitamin D binding protein was analysed in urine and serum samples using Human Vitamin D BP Quantikine ELISA kit (DVDBP0B, R&D Systems, Minneapolis, MN, United States) with a sensitivity of 0.338 ng/ml and with intraassay variability < 2.5% and variability <7% in interassay trials. Urinary Cystatin C (uCysC) levels were analysed using Human Cystatin C ELISA kit from Biovendor (RD191009100, Biovendor, Brno, Czech Republic), with a sensitivity of 0.25 ng/ml, intraassay variability < 4%, and with interassay variability < 11%. Urinary KIM-1 levels were analysed using Human KIM1 ELISA Kit (ab235081, Abcam, Cambridge, United Kingdom) with a sensitivity of 1.28 pg/ml and with intraassay variability <3% and interassay variability <7%. Each immunoassay was performed according to the providers’ protocol. Concentrations of the proteins in urine were expressed per total protein content in the same sample to correct for difference in total protein concentration.