Analytical performance of 4 automated assays for measurement of cystatin C

We evaluated the analytical performance of 4 cystatin C assays (Siemens N Latex on BNII, Roche Tina-quant on Cobas c501, Genzyme on Cobas c501, and Tosoh ST AIA-PACK on Tosoh AIA-600II) according to guidelines published by the Clinical and Laboratory Standards Institute. We evaluated total imprecision, limit of detection, and limit of quantification for each assay using patient serum pools and linearity/recovery using serial dilutions of a patient serum pool with cystatin C-free serum. We compared patients (n = 102) using the Siemens assay as a comparison method. All assays had limits of detection and quantification