Abstract
Technetium-99m-DTPA has previously been proposed as an appropriate radiopharmaceutical for the determination of glomerular filtration rate (GFR). Some 99mTc-DTPA preparations have been found to be inadequate for estimating the GFR because of partial binding of the 99mTc-DTPA to plasma proteins. This protein bound entity which cannot be filtered by the glomerulus results in an error in the calculated GFR from plasma clearance. Our methods use a single injection and either one or two blood samples to estimate the GFR utilizing a protein-free ultrafiltrate of the plasma. Both the one-sample and two-sample methods are easy to perform. The one-sample method is sufficiently accurate for clinical use. The two-sample method is suggested for investigational purposes where special accuracy is required. The technique employed in both of these methods to correct for protein binding results in an accurate estimate of the GFR using 99mTc-DTPA.
Footnotes
↵† University of Alabama, Birmingham, Alabama
