Serum Creatinine, Cystatin C, and -Trace Protein in Diagnostic Staging and Predicting Progression of Primary Nondiabetic Chronic Kidney Disease

BACKGROUND: Impaired baseline kidney function is a well-defined risk factor for progression of chronic kidney disease (CKD).Weevaluatedmeasured glomerular filtra-tion rate (GFR) and the serummarkers creatinine, cysta-tin C, and -trace protein (BTP) for diagnostic accuracy in defining the stage of kidney impairment and as risk predictors of CKD progression. METHODS: Wemeasured serummarker concentrations in 227 patientswith primary nondiabeticCKDand var-ious degrees of renal impairment and followed 177 pa-tients prospectively for up to 7 years to assess progres-sion of CKD. RESULTS: Atbaseline, creatinine, cystatinC, andBTPwere strongly correlated with GFR as measured by iohexol clearance. Concentrations of all 3markers increased pro