title: Accuracy and reproducibility of a new contrast clearance method for the determination of glomerular filtration rate.
abstract: A new method for determining the glomerular filtration rate was analysed prospectively. The method uses an x ray fluorescence technique to measure disappearance from the plasma of injected non-ionic iodinated contrast media. Eighty seven patients were studied. Fifty four had an intravenous dose of 100 ml iohexol (Omnipaque) and 33 had 50 ml iohexol. Clearances of chromium-51 labelled edetic acid (51Cr-EDTA) were measured simultaneously. In the patients given 100 ml iohexol there was excellent correlation with 51Cr-EDTA clearance (r = 0.90). The correlation using 50 ml iohexol was also good (r = 0.85). Correlation between creatinine clearance and clearance of 51Cr-EDTA in 33 patients was less satisfactory (r = 0.69). There were no adverse reactions to the contrast media. The equipment used for measuring contrast clearance was robust and simple to operate. Freezing plasma samples in 10 studies and re-examining them weekly for six weeks showed no significant variation in results; hence reproducibility was good. This new and accurate method for determining the glomerular filtration rate merits further study and might find a useful place in routine clinical practice.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002860:Chromium Radioisotopes; D003287:Contrast Media; D004492:Edetic Acid; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D014283:Triiodobenzoic Acids
chemical_list: D002860:Chromium Radioisotopes; D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; D004492:Edetic Acid