[Evaluation of equations using cystatin C for estimation of the glomerular filtration rate in healthy adult population of canidates for kidney donors.].

The determination of the glomerular filtration rate (GFR) is critical for the selection of potential kidney donors. Methods of measurement of GFR are impractical and complex, which led to development of equations to estimate GFR. Objective: To evaluate of the performance of Creatinine and Cystatin C based equation for estimation of GFR in healthy adult population of candidates for kidney donors. Materials and Methods: a cross-sectional study was performed in 72 adult patients evaluated as candidates for kidney donors. GFR was measured by nonradiolabeled Iothalamate clearence (mGFR). GFR was estimated by the Modification of Diet in Renal Disease (eGFR MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration study (eGFR CKD-EPICREAT, eGFR CKD-EPI-CREAT+CYSC) and the equation proposed by Stevens et al. (STEVENSCREAT+CYSC). The overall performance of all equations was analyzed. Results: eGFR CKD-EPICREAT+CYSC, eGFR STEVENS CREAT+CYSC and eGFR CKD-EPI-CREAT presented lower bias (1,93; - 0,71; -1,53 mL/ min/1,73m2 respectively) compared with eGFR MDRD (bias= -10,36 mL/min/1.73m2). This study demonstrated that the best diagnostic performance was shown by eGFR CKD-EPICREAT+CYSC (LR(+)=9,8; “Positive Likelihood Ratios”), followed by eGFR STEVENSCREAT+CYSC (LR(+)=4,7) and eGFR CKD-EPICREAT (LR(+)=3,7). Discussion: CKD-EPICREAT+CYSC, STEVENS-CREAT+CYSC and CKDEPI-CREAT equations demonstrated a clearly higher performance to estimate GFR compared with MDRD in the study population.