Estimation of GFR Using Iohexol Plasma Clearance in Korean without Renal Disease

Kang, Woo Heon; Kwon, Tae Geun; Kim, Dae Joong; Kang, Myoung Jae; Baek, Hyeon Jung; Yeo, Ho Myoung; Lim, Young Hwan; Kim, Jung Ah; Lee, Bang Hoon; Kim, Beom; Lee, Kyu Beck; Huh, Wooseoung; Kim, Yoon Gu; Oh, Ha Young

Abstract

BACKGROUND
Plasma clearance of iohexol (Omnipaque(r)) which used widely in radiologic procedure is considered as useful method for estimation of GFR because iohexol is neither reabsorbed nor secreted from tubule after filtered as inulin and its extrarenal clearance is negligible. Plasma clearance of iohexol can be calculated from two compartment model or one compartment model with Brochner-Mortensen (B-M) modification which convenient and reliable. But there were controversies about sufficient sampling numbers and times for B-M modification of iohexol clearance. METHODS: Nineteen healthy Korean without renal disease underwent measurement of iohexol clearance. Iohexol was given as a single iv dose, and 14 blood sample were drawn up to 300 min. A reference GFR was iohexol clearance calculated from two-compartment model using 14 samples (CL-T). From 8, 3 and 2 samples clearances were calculated by B-M modification (CL-M8, 3 and 2 respectively). The accuracy of estimates was evaluated as percent of estimates falling within 10% above or below the reference GFR. Accuracy of CCr and equations for GFR estimation were also compared. RESULTS: CL-T, CL-M8, CL-M3 and CL-M2 were not different (101.9+/-24.0, 101.9+/-18.7, 101.7+/-18.6, 101.9+/-19.5 mL/min/1.73 m2 respectively). Accuracy of CL-M8, 3 and 2 were not different (74%, 84% and 79% respectively, p>0.05). MDRD equation had higher accuracy (47%) compared with other equations. CONCIUSION: These results indicate that sampling number for measuring iohexol plasma clearance using simplified method might be reduced to only two without accuracy loss in Korean without renal disease.