A new quantitative method for estimating glomerular filtration rate and its clinical value

Summary Background and aim The estimation of the glomerular filtration rate ( GFR ) is essential for the renal function. However, all estimation methods for GFR have advantages and disadvantages. The aim of this study was to develop a new quantitative method for estimating GFR and evaluate its clinical value. Methods The new GFR was estimated by quantifying the accumulation of T c‐99m DTPA in the dual kidneys and bladder during a gamma camera renogram study in 116 patients with chronic kidney disease. GFR was determined by this new method (n GFR ), G ates' gamma camera technique (g GFR ), a two‐plasma sampling method (t GFR ) and creatinine‐based clearance as estimated by C ockcroft– G ault (c GFR ) and abbreviated MDRD (a GFR ) formulae. The correlation analysis, B land– A ltman analysis and receiver‐operating characteristic ( ROC ) plots were carried out among above methods. Results The n GFR value has significant correlation with t GRF ( r  = 0·827, P <0·01). The n GFR had the best overall performances with a lowest bias deviation (3·1 ml min −1 /1·73 m 2 ), better precision (53·0 ml min −1 /1·73 m 2 ), narrowest interquartile range (13·5 ml min −1 /1·73 m 2 ) and best accuracy (68·1%) within 30% of the t GFR , compared with those of g GFR , c GFR and a GFR . The new method had the similar maximum accuracy with the G ates' method and creatinine clearance as estimated by C ockcroft– G ault and abbreviated modification of diet in renal disease ( MDRD ) method. The new method had better repeatability characteristic compared with the G ates' method. Conclusions The new method for estimating GFR had the better performances compared with the G ates' method and creatinine clearance as estimated by C ockcroft– G ault and MDRD method.