Assessment of Common Serum Renal Function Tests in Elite Athletes: A Systematic Review and Meta-analysis

Background and Purpose Renal function test results may be influenced by a variety of lifestyle and dietary factors that may substantially differ between elite athletes and the general population. Currently, there are no athlete-specific reference limits for renal function tests, and reliance on general population thresholds may lead to diagnostic uncertainty. This review aimed to provide guidelines for the use of renal function tests in elite athletes. Design Systematic review and meta-analysis. Method PubMed/MEDLINE, EMBASE, Scopus, and Cochrane Library databases were searched on July 14, 2025, and January 15, 2026. Eligible studies included randomized controlled trials, observational studies, and case series evaluating serum creatinine, cystatin C, urea, and/or glomerular filtration rate (GFR) values in adolescent or adult elite athletes. Results Forty-nine studies were included, yielding a total sample of 5 338 athletes across 16 sports. The mean age was 26.9 years and the mean BMI was 23.05 kg/m 2 . Pooled mean baseline values for the most commonly reported renal function tests were serum creatinine 0.97 mg/dL, serum urea 33.6 mg/dL, eGFR (CKD-EPI) 98.96 mL/min/1.73 m 2 . Endurance athletes demonstrated a significantly lower pooled mean baseline serum creatinine level than did non-endurance athletes. Conclusions This review demonstrates that the mean values for commonly reported renal function tests, including creatinine, urea, and eGFR (CKD-EPI), fall within the standard reference limits used for the general population. This trend applies when sports are categorized into endurance and non-endurance subgroups. We conclude that the standard population reference ranges for creatinine, urea, and eGFR (CKD-EPI) can be applied to elite athletes.