How to Do a Radioisotope Glomerular Filtration Rate Study

Abstract

Glomerular filtration rate (GFR) can be measured by the blood clearance of any tracer that is cleared through the kidneys solely by glomerular filtration. Nuclear medicine is ideally suited to this because it uses minute tracer quantities of radioisotope that do not disturb kidney function and gives a very low radiation dose. The method involves blood sampling alone and so is helpful when urine collection is difficult. It is, therefore, more reliable than creatinine clearance, which requires 24-h urine collection, and is more accurate than the eGFR, which is based on a serum creatinine measurement in isolation. However, it only gives total renal clearance, and so individual differential kidney clearance can be inferred in combination with either a renogram or DMSA scan.