Monitoring Renal Function: A Prospective Study Comparing the Camera-Based Tc-99m MAG3 Clearance and Creatinine Clearance

• Type of Material: Article
• Authors: Raghuveer Halkar, Emory University; Andrew T Taylor Jr., Emory University; Amita Manatunga, Emory University; Muta M Issa, Emory University; Samuel E Myrick, Emory University; Sandra Grant, Emory University; Neeta V. Shenvi, Emory University
• Language: English
• Date: 2007-03
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2007 Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.urology.2006.11.026
• Title of Journal or Parent Work: Urology
• ISSN: 0090-4295
• Volume: 69
• Issue: 3
• Start Page: 426
• End Page: 430
• Grant/Funding Information: This work was partially supported by a grant from the National Library of Medicine, ROI LM 007595 and by a grant from Mallinckrodt, Inc.
• Keywords: renal function; Tc-99m mercaptoacetyltriglycine; camera-based MAG3 clearance; creatinine clearance
• Research Categories: Biology, Biostatistics; Health Sciences, Radiology

Abstract

Objectives To determine the value and limitations of Tc-99m MAG3 clearance measurements obtained using a gamma camera (camera-based MAG3 clearance), a prospective study was conducted to evaluate the reproducibility of the camera-based MAG3 clearance compared to that of the conventional creatinine clearance. Materials and Methods Twenty-four male patients with stable renal function entered the study; the mean age was 66.5 ± 7.9 years and the mean serum creatinine was 1.38 ± 0.57 mg/dL. MAG3 renal scans and 24-hour creatinine clearance measurements were performed 11 ± 8 days apart. A camera-based MAG3 clearance was obtained at the time of each MAG3 scan; no blood samples were required. Bland-Altman plots were constructed to assist in data analysis. Results The Pearson correlation for the first and second camera-based MAG3 clearances (means of 151 vs 158 mL/min/1.73m2, respectively) was 0.965 compared to 0.729 for the two creatinine clearance measurements (means of 62 vs 72 mL/min/1.73m2, respectively). Even with the omission of two outliers, the creatinine clearance would have to change by 58.2% compared to the baseline measurement before the clinician could be confident the change exceeded the error of measurement; in contrast, the change required for the camera-based MAG3 clearance was 30.8%. Conclusion This study demonstrates that MAG3 clearance obtained using a camera-based technique shows greater precision than the conventional creatinine clearance and is superior to the creatinine clearance for monitoring changes in renal function.