Research Article

Accuracy and reproducibility of a new contrast clearance method for the determination of glomerular filtration rate.

Br Med J (Clin Res Ed) 1986; 293 doi: http://dx.doi.org/10.1136/bmj.293.6541.234 (Published 26 July 1986) Cite this as: Br Med J (Clin Res Ed) 1986;293:234
  1. P H O'Reilly,
  2. P J Brooman,
  3. P J Martin,
  4. A J Pollard,
  5. N B Farah,
  6. G C Mason

    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.