Accuracy of Shorter Iohexol Glomerular Filtration Rate Measurement Protocols in Individuals with Preserved Kidney Function.

BACKGROUND

Measuring glomerular filtration rate (mGFR) using exogenous tracers is recommended in a number of settings. Plasma one-compartment multi-sample protocols (MSP) are the most commonly used with iohexol being the dominant tracer. The accuracy of MSP protocols has mostly been evaluated in the setting of reduced GFR where delayed initial and final samples are recommended. Much less is known about MSPs when GFR is not decreased, and the default protocol tends to include initial sampling at 120 minutes (min) and final sampling at 240 min post iohexol injection. The recent KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease includes research recommendations for the development of shorter more efficient mGFR protocols. The objective of this study was to assess the performance of shorter MSPs with earlier initial (60 and 90 min) and final (150, 180, and 210 min) sampling times in individuals with preserved GFR. Reference mGFR was calculated using 5 samples collected between 120-240 min.

METHODS

Four different combinations of shorter sampling strategies were investigated. Performance was evaluated using measurements of bias, precision, and accuracy (P2, P5, and mean absolute error).

RESULTS

The mean reference mGFR of the 43 participants was 102.3 ± 13.7 ml/min/1.73m2. All shorter mGFRs had biases less than 1 ml/min/1.73m2 and mean absolute error less than 1.6 ml/min/1.73m2. All shorter mGFRs were within 5% of the reference mGFR, and the majority were within 2%.

CONCLUSIONS

These results demonstrate that shortening the mGFR procedure in individuals with preserved GFR provides similar results to the current standard while significantly decreasing procedure time.

Informations de copyright

Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Nephrology.