In situations where complete urine collections are difficult to obtain, single-injection methods have been recommended for the assessment of glomerular filtration rates (GFRs) without recourse to urine collections.1-6 These methods have generally used millicurie doses of isotope or smaller doses and scanning equipment. This report describes the effectiveness of technetium Tc 99m pentetate at a dose of 1 to 2 μCi/kg for the assessment of GFR.
Methods.—The technetium Tc 99m pentetate was prepared from a commercial kit, diluted to 1 to 2 μCi/kg in approximately 3 mL of physiologic saline, and placed in a plastic syringe. After weighing the syringe on an analytical balance, 0.1 mL was injected into a 100-mL volumetric flask for use as a counting standard, and the syringe was reweighed. The remaining solution was injected into the subject's vein through a butterfly needle, the butterfly was flushed with 10 mL of saline, the time