Is Iohexol a Possible Method for Estimating Glomerular Filtration Rate?

The measurement of glomerular filtration rate (GFR) is essential in diagnosing and managing chronic kidney disease (CKD) and autosomal dominant polycystic kidney disease (ADPKD), both requiring precise renal function assessment. Traditionally, GFR has been estimated using endogenous markers like creatinine and cystatin C, though these can be inaccurate due to factors unrelated to kidney function, such as muscle mass and diet. The iohexol clearance method provides a more accurate and less invasive alternative to traditional markers like inulin or radioactive markers. Iohexol, a non-ionic, water-soluble contrast agent, is exclusively eliminated by glomerular filtration, making it highly suitable for direct GFR estimation. This paper describes procedures for iohexol clearance, involving defined-interval blood samples after intravenous administration. In patients with normal renal function, sampling intervals are more frequent, while in advanced CKD patients, including those with ADPKD, slower iohexol elimination requires wider intervals to ensure accurate clearance analysis. Iohexol has demonstrated high precision and reproducibility, even compared to other markers. Research supports using iohexol to monitor CKD and ADPKD progression effectively. Particularly in ADPKD, iohexol detects subtle but clinically significant GFR changes, even in early disease stages, making it valuable for evaluating targeted therapies. However, iohexol use is limited to specialized centers due to high costs and strict protocols. Its implementation in advanced European healthcare facilities underscores its efficacy, providing reliable GFR estimates that enhance nephrology practice, despite some limitations.