Determination of glomerular filtration rate by non-ionic contrast medium iohexol plasma clearance

Objective To evaluate the determination of glomerular filtration rate (GFR) by non-ionic contrast medium iohexol plasma clearance. Methods GFR of 93 patients, 45 male and 48 female, age ranged from 12 to 80, with different renal functions was determined. The patient underwent an overnight fast and 5 ml of iohexol was injected into peripheral vein in the morning. 2 ml plasma sample was collected 4 hours after injection, and plasma concentration of iohexol was measured by high performance liquid chromatography(HPLC) . The iohexol plasma clearance was calculated by two one-compartment model; Jacobsson's and Bubeck's model. 99mTc clearance was used as the reference method. Results Iohexol-GFR obtained by Jacobsson's model vs 99mTc-GFR yielded a correlation of r = 0. 85, standard error of the estimate (SE) = 16. 06 ml/min. There was also a high correlation between iohexol-GFR obtained by Bubeck's model and 99mTc-GFR, r = 0. 82, SE = 17. 75 ml/min. In the patients in early stage of renal failure, iohexol-GFR was the most sensitive indication as compared to Scr and Ccr. Conclusion Iohexol plasma clearance calculated by Jacobsson's and Bubeck's models is a simple and accurate method of determining GFR.