A simple chemical method for the quantification of the contrast agent iohexol, applicable to glomerular filtration rate measurements

We present a method for the quantification of the contrast agent iohexol in serum. Iohexol is deiodinated by alkaline hydrolysis and the released iodine subsequently measured according to the ceric arsenite method. The assay requires 50 microliters of serum and has a high capacity as it involves few analytical steps. The high precision (2% CV) and sensitivity make the method applicable to the recently developed procedure for the determination of glomerular filtration rate, which is based on the assessment of the clearance of iohexol from serum. The method is simple and rapid and requires no expensive equipment.