Abstract
Glomerular filtration rate (GFR) is the best indicator of the renal function. Gold standard for GFR measurement is inulin clearance (Cin). However, its measurement is inconvenient, time-consuming, and non-economic. Thus, in both scientific studies and routine clinical practice Nuclear medicine methods (99mTc DTPA, 51Cr EDTA) are preferred, which are highly correlated with Cin. In addition, recently cystatin C (Cys) and beta trace protein (BTP) are also used for this purpose. In literature, however, data are limited about the clinical value of Cys and BTP in GFR measurement in CKD cases and the results have been inconclusive. In this study, we aimed to determine the efficiency of Cys and BTP in determina-tion of GFR in CKD patients. A total of 84 (59 males, 25 females) CKD patients aged 21 to 88 years (mean 61 years) were included criteria. GFR was calculated with three different methods: 1) using the gold standard DTPA two plasma sample method (TPSM); 2) using formula containing Cys to calculate GFR ; 3) using formula containing BTP. Correlation of GFR values calculated with Cys and BTP with that obtained with DTPA TPSM was assessed. GFRs calculated with both methods were significantly correlated with that calculated with gold standard method. However, GFR values obtained with Cys had a better correlation compared to those of BTP. Using Bland Altman analysis, scatter graphics of the differences between GFR values calculated using DTPA TPSM and those calculated with Cys, BTP at a confidence interval of 95% (mean ± 1.96SD). The GFR values obtained with Cys and BTP did not have reliable consistency. As a conclusion, we showed that GFR values calculated with Cys and BTP failed to show GFR of the CKD. Based on these results, our study demonstrated that Cys and BTP is not sufficient in reflecting GFR.