THE RELATION OF SPECIFIC GRAVITY TO COMPOSITION AND TOTAL SOLIDS IN NORMAL HUMAN URINE 1

Abstract

The sp.gr. of urine is a simple additive function of cone, of its individual solutes. 48 24-hr, urines from 6 normal subjects were analyzed for chlorides, sulfate, phosphate, bicarbonate, urea, creatinine, and total solids, Urea contributed 15-20%, chlorides 25-30%, sulfate plus phosphate 15-25%, bicarbonate 1-5%, and creatinine 1-2% of the observed sp. gr. The undetd. fraction of sp. gr. comprised 10-30% of the observed value and in the same urines the excretion of undetd. solids amounted to 10-15 g. daily, or from 10-30% of the total solids. Organic acids made up about 1/2 of this fraction. The various coefficients proposed for estimation of total solids from sp. gr. are valid only for urines of the same relative composition.