Introduction: The aim of this study was to compare two gamma camera-based methods (Gates' method and Inoue's method) for measuring glomerular filtration rate (GFR) with Russell's two plasma sample clearance method (2-PSC), which was taken as the gold standard.
Materials and methods: In 94 healthy potential kidney donors (25 women and 69 men), GFR was measured by means of the 2-PSC method and was compared with Gates' and Inoue's methods of assessing GFR after technetium-99m-labeled diethylene triamine penta-acetic acid (⁹⁹ mTc-DTPA) injection.
Results: Inoue's method showed no statistically significant difference (P=0.22) with the gold standard (2-PSC); there was good correlation (r=0.69) and least bias (-1.91 ml/min/1.73 m², root mean squared error=11.85 ml/min/1.73 m²). Gates' method showed weak correlation (r=0.36) and tended to underestimate GFR by 21% with bias of 25 ml/min/1.73 m² and root mean squared error of 29.97.
Conclusion: For a normal healthy adult population, Inoue's method gives a better measure of GFR in contrast to Gates' method when compared with 2-PSC method of GFR calculation.