#2422 Iohexol plasma clearance measurement protocol standardization—a consensus of the European Kidney Function Consortium

Abstract Background and Aims International consensus supports the development of standardized protocols for measured glomerular filtration rate (mGFR) to facilitate the adoption of mGFR determination in both clinical and research settings. Method The European Kidney Function Consortium (EKFC) convened an international group of mGFR experts. The working group performed an extensive literature search to inform the development of recommendations for mGFR determination using one-compartment plasma clearance models and iohexol as the exogenous filtration marker. Iohexol was selected as it is non-radio labeled, inexpensive, widely available, and can be assayed at a central laboratory. Other commonly used non-radio labeled tracers have been (inulin) or are soon to be (iothalamate) discontinued. A plasma clearance model was selected as it requires no timed urine collections. A one-compartment model was preferred to a two compartment model as it requires fewer samples. The resulting recommendations were based on published evidence complemented by expert opinion. Results Recommendations include practical advice for patients and health professionals, preparation, administration and safety aspects of iohexol, laboratory analysis, blood sample collection and sample timing for both multiple and single sample protocols, description of the mGFR mathematical calculations as well as implementation strategies (Fig.). EKFC will provide materials such as patient information sheets, standard operating procedures, a study protocol template, and support for mGFR calculation. Conclusion Members of the EKFC have evaluated the evidence and formulated recommendations that include all aspects of iohexol plasma clearance measurement using a one compartment model. *Author list on behalf of the European Kidney Function Consortium (EKFC).