INDIVIDUAL KIDNEY GLOMERULAR FILTRATION RATE USING RADIONUCLIDES

Abstract

The accuracy of a simple new method for glomerular filtration rate (GFR) was assessed by comparing it with the established multiple plasma sampling method in 101 consecutive children having a renal scan and serum B2 microglobulin assay (B2M). A. Multiple plasma sampling method (M Plasm). Following a measured IV dose of technetium DTPA, this was calculated conventionally following samples at 120, 150 & 180 minutes. B. Following the same dose of radionuclide, the information from a gamma camera viewing kidneys and precordium was captured onto a digital computer. From this information counts accumulating in the individual kidneys due to GFR were computed. A single plasma sample taken 20 minutes after injection furnished the plasma counts. From these two parameters individual kidney GFR was calculated. C. B2M was measured by radioimmunoassay using Phadebas B2M kit. The new method correlated well with M Plasm (r=0.80) and with B2 microglobulin (r= -0.86). The correlation between M Plasm and B2M was also good (r= -0.92). This new method is inherently attractive because: 1. It can be performed during the course of a normal renal scan without added radiation or trauma to the patient. 2. It is completed in 20 minutes. 3. It is theoretically applicable to patients with oedema or localised effusions. 4. It provides information with respect to individual kidney function.