Evaluation of glomerular filtration rate estimation through plasma clearance of iohexol in seagulls (Larus michahellis)

Background: Current endogenous indicators utilised in avian medicine are not sensitive enough to detect renal disease in its early stages. Alternative markers ought to be examined as a result. The aim is to investigate the accuracy of limited-sampling models for glomerular filtration rate (GFR) in adult seagulls using plasma clearance of iohexol (IOX). Results: We compared the GFR estimated from the plasma concentration of IOX at 3 sampling times, known as limited sampling models, with that estimated from the plasma concentration of IOX at 6 sampling times (reference model). The reference model’s mean ± SD for GFR was 6.88 ± 2.46 mL/min/kg and did not considerably differ from the GFR predicted by the limited-sampling models. Model 4, in which GFR was estimated using plasma IOX concentrations at 5, 15, and 90 min after IOX administration, had the smallest GFR bias compared to the reference model. Conclusions: The findings revealed that IOX plasma clearance was a reliable, accurate, and clinically applicable approach to calculating seagull GFR. This strategy might help with the validation and subsequent development of clinical renal biomarkers.