Aim: Since glomerular filtration rate (GFR) determined by 24 hours urine is cumbersome, nephrologists recommend using an estimated GFR (eGFR). This study aimed to investigate the agreement between Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR in high case numbers.

Materials and Methods: 56228 eGFR results were included in the study. For agreement between MDRD and CKD-EPI eGFR results, kappa analysis was used. Additionally, the two methods were compared according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

Results: The category agreement between the two eGFR methods was 84.4%, while the discordance was 15.6%. Incompatibility was found as 3.0%, 33.2%, 13.0%, 7.2% and 1.1% from (GFR category) G1 to G5, respectively. CKD-EPI eGFR results were average 4.4% higher than MDRD. When Chronic Kidney Disease (CKD) stage transition limits were taken as the medical decision limit, the highest difference% was determined to be 9.8% at stage 1-2 transition.

Conclusion: Although the difference between the two methods is <9.8%, the 15.6% categorical discordance will create a follow-up problem in patient monitoring; it also shows that it is not appropriate to use it in a healthy population, given that MDRD produces higher results in low serum creatinine.