Beta trace protein as GFR marker in children

Background and Objective: Serum creatinine is the most used endogenous marker of glomerular filtration rate (GFR), but it also has multiple limitations. Therefore, some surrogate GFR markers, such as beta trace protein, have been introduced for GFR estimation. The aim of our study was to estimate GFR by serum beta trace protein using three available equations and compare them to DTPA GFR as the gold standard and Schwartz GFR. Methods: The three beta trace protein (BTP)-related GFR formulas were the White formula (1): GFR=167.8×BTP-0.758×creatinine-0.204, Pöge formula (2): GFR=974.31×BTP-0.2594×creatinine-0.647, and Benlamri formula (3): GFR=10^ (1.902+ (0.9515×LOG (1/BTP)). Twenty seven children were included in this study. All patients had a Schwartz and DTPA GFR more than 50 cc/min/1.73m2. Results: We showed that there was no significant correlation between DTPA GFR and Schwartz-estimated GFR (r= -0.1, Pv= 0.5). There also was not any association between GFR estimated by Pöge and Benlamri formulas and DTPA scans. In contrast, there was a significant association between DTPA GFR and White BTP formula-estimated GFR (r=0.77 r=0.00). Conclusion: This study showed that GFR estimated by serum beta trace protein and White formula had accuracy over Schwartz formula in children with normal or mild reduced GFR however, this result needs to be confirmed by additional studies with more cases.