The aim of this study was to investigate the value of cystatin C and beta-trace protein (BTP) levels in determination of the glomerular filtration rate (GFR) by accepting the technetium-99m diethylenetriamine pentaacetic acid (99mTc-DTPA) method as the gold standard for GFR measurement in renal transplant patients with stable renal functions and to investigate the value of cystatin C and BTP levels in the determination of GFR in cases with or without renal tubular injury.Methods
A total of 89 (60 men and 29 women) renal transplant patients aged 19–67 years (mean 38.15 years) with stable graft functions were included in the study. GFR was calculated using three different methods: (a) the 99mTc-DTPA two plasma sample method; (b) eight different formulas containing cystatin C; and (c) three different formulas containing BTP. In addition, the cases were divided into two groups on the basis of N-acetyl-β-D-glucosaminidase and β2 microglobulin levels showing tubular damage.Results
GFR values obtained with cystatin C had a better correlation with the gold standard method compared with those obtained with BTP, and the GFR value obtained with cystatin C had the most reliable consistency. We found that cystatin C provided more accurate results in GFR follow-up in renal transplant patients with no tubular injury compared with those with tubular injury.Conclusion
Cystatin C is a good marker of GFR in renal transplant patients, especially in those with no tubular injury; however, BTP is not as good as cystatin C in that regard.