Comparison of the consistency between interns in accurate quantification of split kidney glomerular filtration rate

The aim of this study was to evaluate the consistency of an innovative method that combines ⁹⁹Tc^m-diethylene triamine pentaacetic acid (DTPA) renal dynamic imaging with ⁹⁹Tc^m-DTPA dual plasma clearance to precisely quantify the split kidney glomerular filtration rate (sk-GFR).

154 patients were prospectively included in this study and underwent renal dynamic imaging using ⁹⁹Tc^m-DTPA (Gate's method, g-GFR) and the dual plasma clearance method (true glomerular filtration rate [t-GFR]). Our team developed an innovative method to precisely determine sk-GFR based on the ⁹⁹Tc^m-DTPA dual plasma clearance method combined with the simplified Gate's method (g'-GFR). The precise sk-GFR was calculated based on the following formula: precise glomerular filtration rate (p-GFR_left) = g'-GFR_left/(g'-GFR_left + g'-GFR_right) × t-GFR. The variability and consistency of sk-GFR, calculated by four interns, were assessed using paired t-test, Pearson's correlation, and Kendall's W test. Furthermore, the consistency among the four interns with two methods was assessed across different stages of renal dysfunction.

All four interns used both methods to measure sk-GFR. Although three interns achieved consistent results, one intern reported significantly lower sk-GFR values than the others. Four interns used Gate's method with a g-GFR_left Kendall's W coefficient of 0.846 and g-GFR_right Kendall's W coefficient of 0.776. Additionally, they used an innovative method, which resulted in a Kendall's W coefficient of 0.967 for both p-GFR_left and p-GFR_right. The consistency of sk-GFR using the innovative method was higher than that using the Gate's method at different stages of renal dysfunction.

The innovative method provided a standardised procedure for estimating sk-GFR, thereby offering more reliable estimates by less experienced interns.