Despite Smith's1 demonstration that under proper conditions the plasma clearance of diodrast closely approximates renal plasma flow, the detection of renal ischemia in human beings is evidently not a simple matter. Its existence in patients with hypertensive disorders has been claimed by some authors2 and denied by others.3 This report on a small series of subjects with normal and with diseased kidneys attempts to reconcile these divergent statements.
Since no ratios for diodrast extraction based on human material have been published, the validity of the clearance method of measuring renal blood flow clinically is not conclusively established. Indirect evidence, however, suggests that the agreement between actual blood flow and estimated blood flow is even closer in human beings than in dogs.4 There being no reason to doubt that the plasma clearance of inulin is an accurate measure of the rate of glomerular filtration,5 the ratio
FINDLEY T, EDWARDS JC, WHITE HL. CLEARANCE OF DIODRAST, PHENOLSULFONPHTHALEIN AND INULIN IN HYPERTENSION AND IN NEPHRITIS. Arch Intern Med (Chic). 1942;70(6):935-947. doi:10.1001/archinte.1942.00200240019002