JOURNAL OF NUCLEAR MEDICINE TECHNOLOGY, cilt.43, sa.3, ss.206-213, 2015 (ESCI)
Glomerular filtration rate (GFR) is the best indicator of renal function. The gold standard for GFR measurement is inulin clearance. However, its measurement is inconvenient, time-consuming, and costly. Thus, in both scientific studies and routine clinical practice nuclear medicine methods (Tc-99m-diethylenetriaminepentaacetic acid [Tc-99m-DTPA] and (51) Cr-ethylenediaminetetraacetic acid [Cr-51-EDTA]) are preferred, and they correlate strongly with inulin clearance. In addition, cystatin C and (beta-trace protein have also recently been used for this purpose. In the literature, however, data are limited about the clinical value of cystatin C and (beta-trace protein in GFR measurement in chronic renal disease (CRD), and the results have been inconclusive. In this study, we aimed to determine the efficiency of cystatin C and (beta-trace protein in the determination of GFR in CRD patients. Methods: Eighty-four patients with CRD were included in the study (59 men and 25 women; age range, 21-88 y; mean age, 61 y). GFR was calculated using the goldstandard Tc-99m-DTPA 2-sample plasma sampling method (TPSM) and 2 alternative methods: a formula using cystatin C and a formula using (beta-trace protein. The correlation between TPSM and the cystatin C and (beta-trace protein methods was assessed, and Bland-Altman analysis was used to graph scatterplots of the differences at a confidence interval of 95% (mean difference +/- 1.96 SDs). Results: GFRs calculated using both alternative methods correlated strongly with those calculated using the gold standard. However, the correlation was stronger for the cystatin C method than for the (beta-trace protein method, and neither method produced reliably consistent GFRs. Conclusion: This study demonstrated that cystatin C and (beta-trace protein do not reflect GFR with sufficient accuracy.