RT Journal Article SR Electronic T1 Determination of Glomerular Filtration Rate Using Technetium-99m-DTPA with Differing Degrees of Renal Function JF Journal of Nuclear Medicine Technology JO J. Nucl. Med. Technol. FD Society of Nuclear Medicine SP 110 OP 114 VO 25 IS 2 A1 Morton, Kathryn A. A1 Pisani, David E. A1 Whiting, John H. A1 Cheung, Alfred K. A1 Arias, John M. A1 Valdivia, Sonia YR 1997 UL http://tech.snmjournals.org/content/25/2/110.abstract AB Glomerular filtration rate (GFR) is an important index of renal function. Twenty-four-hour creatinine clearance overestimates GFR in patients with poor renal function. Inulin and iothalamate clearances are accepted reference standards for determining GFR but are expensive and laborious. We have previously reported that GFRs obtained by measuring the disappearance of 99mTc-DTPA from ultrafiltered (protein-free) samples of plasma were virtually identical to those obtained by the iothalamate method. However, the subjects used in that study had normal to only moderately decreased renal function. Methods: The accuracy of measuring GFR by plasma clearance of 99mTc-DTPA was determined in subjects where renal function varied from normal to severely impaired. In all subjects, GFR was established by clearance of 125I-iothalamate from urine and serum and was used as the standard of reference. Results: For subjects with normal to moderately diminished renal function (GFR > 20 ml/min), the correlation between values of GFR obtained by the DTPA and iothalamate methods was high (n = 18, r = 0.966). The difference between the pairs of GFR values obtained by the two methods was not statistically significant (p > 0.1). In patients with severe renal insufficiency (GFR < 20 ml/min), the correlation between the DTPA and iothalamate methods was poor (n = 11, r = 0.236), and the GFR values obtained by the two methods were statistically different (p < 0.01). Conclusion: These results suggest that GFR can be determined accurately by plasma clearance of 99mTc-DTPA in all patients except those with severe renal insufficiency.