ABSTRACT
One of the important functions of the kidney is to excrete waste material and substances for which the body has no immediate need. Under most circumstances, more solid leaves the body by way of the urine than by any other route. Although there are thousands of different compounds in a typical urine specimen, the major portion of the solid is ordinarily sodium chloride and urea. The quantity of sodium chloride is from 5 to 25 g/24 hr, and the amount of urea excreted during this time is from 10 to 40 g. The salt content of the urine reflects the amount of salt in the diet, and the urea content reflects the amount of dietary protein. Urine density is related primarily to the amount of water excreted and the amount of salt and urea present. Under most situations, the specific gravity of human urine is between 1.008 and 1.030.
