CAPILLARY ELECTROPHORESIS FOR THE DETERMINATION OF GLOMERULAR-FILTRATION RATE USING NONRADIOACTIVE IOHEXOL

High-performance liquid chromatography (HPLC) has been used as an alte rnative to the isotopic method to calculate glomerular filtration rate (GFR), With the HPLC method, serum iohexol or iothalamate levels are measured, and the plasma clearance rate of the compound is used as a s urrogate for GFR. However, HPLC is a labor-intensive procedure, which limits its usefulness in the clinical setting, Capillary electrophores is, a newer technique in which electrophoretic separations are perform ed in capillary tubes, is easier and faster than HPLC. We used capilla ry electrophoresis for the determination of serum iohexol levels and t he calculation of GFR, Patients underwent a simultaneous I-125-iothala mate clearance test and a plasma iohexol clearance test to determine G FR, Mean GFR (+/- SD) was 70.9 +/- 29.9 mL/min (range, 14.5 to 131 mL/ min) in 52 patients as determined by standard iothalamate clearance me thods. For iohexol clearance, the correlation coefficient and standard error were 0.93 and 10.9 mL/min, respectively, using capillary electr ophoresis compared with the iothalamate method, Capillary electrophore sis is a simple, rapid method that can be used to calculate GFR and pr ovides results at least as accurate as those obtained by HPLC and x-ra y fluorescence. (C) 1996 by the National Kidney Foundation, Inc.