AIMS: To investigate the agreement of glomerular filtration rate (GFR) determination between Cr-ethylenediaminetetraacetic acid (Cr-EDTA) plasma clearance (GFR) and Tc-diethylenetriaminepentaacetic acid (Tc-DTPA) plasma clearance (GFR), the Gates Tc-DTPA renographic method (GFR) and the serum creatinine Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI, GFR) in patients with type 2 diabetes mellitus (T2DM).METHODS: Ninety-nine T2DM patients underwent GFR determinations simultaneously with Cr-EDTA and Tc-DTPA (using the slope-intercept technique and the Brochner-Mortensen correction) and also with GFR and GFR.RESULTS: In the comparison between GFR versus GFR, GFR and GFR, the Bland-Altman statistic provided 0.0 ± 13.2, 17.4* ± 28.8 and -5.9* ± 30.1 (*p < 0.001 for the difference from 0). Lin's concordance correlation coefficient showed substantial (0.976), poor (0.737) and poor (0.872) agreement, respectively. The proportion of the index results within the 30% and 10% of GFR measurements were 95% and 74% for GFR, 53% and 19% for GFR, and 83% and 26% for GFR, respectively.CONCLUSION: In T2DM patients, a clinically acceptable agreement is demonstrated between Cr-EDTA and Tc-DTPA plasma clearance for GFR measurements, suggesting conditional interchangeability between those compounds. Both the CKD-EPI prediction equation and the Gates' renographic method cannot assess GFR reliably, the latter appearing less unfailing than the former.