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A TEST OF RENAL FUNCTION: EXCRETION OF CONTRAST MEDIUM AS MEASURED BY URINARY SPECIFIC GRAVITY
Author(s) -
Marshall Sumner
Publication year - 1964
Publication title -
british journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 0007-1331
DOI - 10.1111/j.1464-410x.1964.tb09540.x
Subject(s) - excretion , excretory system , contrast medium , urine , urinary system , urology , renal function , urine specific gravity , creatinine , contrast (vision) , medicine , chemistry , endocrinology , physics , radiology , optics
SUMMARY1 The excretion of a contrast medium, measured by specific gravity of the urine, appears to be a valid measure of renal function, as indicated by a close correlation with both PSP excretion and levels of serum creatinine. 2 The maximal ability of the kidneys to excrete the contrast medium is determined by the increase in specific gravity over that of a pre‐injection baseline specimen. 3 With the dosage of contrast medium commonly used for excretory urography, the specific gravity of the urine increases rapidly, persisting at an elevated level for up to two hours. Accurate timing for collection of specimens is, therefore, unnecessary. 4 Since the increase in urinary specific gravity is a measure of the concentration of excreted contrast medium, determinations of volume are unnecessary. 5 An increase in specific gravity of 0.025 unit or greater indicates normal renal function. 6 The test is a most useful adjunct to excretory urography, particularly in cases of poor opacification. 7 The test is accurate, inexpensive, and simply performed.