Human cystatin c elisa

The study samples had a mixture of inulin [40 (link)], iohexol [41 (link)], or ⁵¹Cr-EDTA [42 (link)] GFR measurements as the reference standard. The results were expressed per 1.73 m²-body surface according to the Dubois equation: body surface area = height^0.725 × weight^0.425 × 0.007184. Applied mGFR methods were reported to have sufficient accuracy compared with the inulin method [43 (link)]. All creatinine measurements were performed with methods traceable to the National Institute of Standards and Technology and were isotope-dilution mass spectrometry calibrated [44 (link)]. Serum cystatin C measurements of the Berlin cohort were measured at Labor Limbach Heidelberg (Heidelberg, Germany) using the PENIA N Latex^® assay on the BN™ II System (Siemens Health Care Diagnostics, ex-Dade-Behring, Marburg, Germany). For samples from Lyon and Gothenborg with sufficient leftover volume, cystatin C was measured with the Human Cystatin C ELISA from Biovendor (BioVendor—Laboratornimedicinaa.s., Brno, Czech Republic) calibrated to standard reference material ERM-DA471/IFCC at Laborarztpraxis van de Loo, Schwäbisch Gmünd, Germany.

The study samples contained iohexol [16 (link)], inulin [17 (link)], ⁵¹Cr-EDTA [18 (link)] or iothalamate [19 (link)] as a reference standard for GFR measurements (mGFR). All mGFR methods were reported to have sufficient accuracy compared with inulin clearance [20 (link)]. Measured GFR was normalized to body surface area according to the Dubois equation (body surface area = height^0.725 × weight^0.425 × 0.007184) and expressed as milliliter per minute per 1.73 m² body surface (mL/min/1.73 m²). Enzymatic serum creatinine measurements were performed with methods traceable to the National Institute of Standards and Technology and were isotope-dilution mass spectrometry calibrated [21 (link)]. Serum cystatin C measurements were performed at Mayo Clinic using Gentian Cystatin C Immunoassay ERM-DA471/IFCC standardized (Gentian ASA, Moss, Norway). The Berlin cohort was measured at Labor Limbach Heidelberg using the PENIA N Latex^® assay on the BN™ II System (Siemens Health Care Diagnostics, ex-Dade-Behring, Marburg, Germany). For samples from Lyon cystatin C was measured with the Human Cystatin C ELISA from Biovendor (calibrated to standard reference material ERM-DA471/IFCC, Laborarztpraxis van de Loo, Schwäbisch Gmünd, Germany).