A comparative study of different methods of estimating glomerular filtration rate in a subset of Filipinos with normal renal function
- Author:
Patrick Earl A. Fernando
1
;
Patricia A. Bautista-Peñalosa
1
Author Information
1. Department of Nuclear Medicine and PET Center St. Lukes Medical Center, Bonifacio Global City, Taguig, Philippines
- Publication Type:Journal Article
- Keywords:
Plasma sampling;
99mTc-DTPA;
CKD-EPI equation;
Method-comparison study
- MeSH:
Glomerular Filtration Rate;
Creatinine
- From:
The Philippine Journal of Nuclear Medicine
2020;15(2):8-17
- CountryPhilippines
- Language:English
-
Abstract:
Kidney function is commonly quantified using the glomerular filtration rate (GFR). However, the gold standard of
measuring GFR, inulin clearance, is not practical for daily clinical use. This study compares different methods of
GFR estimation based on serum creatinine, plasma levels of 99mTc-diethylenetriaminepentaacetic acid (DTPA), and
camera acquisition of 99mTc-DTPA uptake. Seventy-five Filipino adults between ages 20 and 35 presumed to have
normal kidneys were recruited. Each subject underwent gamma camera scintigraphy using the Gates and Inoue
protocols after receiving a dose of 99mTc-DTPA. Blood samples were subsequently extracted at 1 hour and 3 hours
after tracer injection, and GFRs were calculated based on single- and double-plasma sampling methods (SPSM and
DPSM, respectively). Serum creatinine was also measured to derive GFR using the CKD-EPI, MDRD, and CockroftGault equations. Each method was correlated with a reference standard (DPSM) based on accuracy, linear
regression, bias, and precision. SPSM tends to overestimate GFR unlike the other methods evaluated, but
otherwise shows the most favorable diagnostic performance among the six methods when correlated with DPSM.
The Inoue method appears modestly better than the routinely utilized Gates protocol, though both methods
exhibit lack of precision. The CKD-EPI formula shows similar, if not slightly superior, diagnostic properties to the
MDRD and Cockroft-Gault equations, thus confirming its validity for use in this Filipino population subset. Further
studies are needed, particularly involving SPSM and CKD-EPI, to determine the applicability of our findings in
Filipinos with varying degrees of kidney function. It is hoped that modifications to these methods can be made that
are tailor-fit to derive more accurate and population-specific GFR values.
- Full text:A Comparative.pdf
