Creatininemia Versus Uremia

Abstract

The physiology of urea and creatinine production by the body and excretion by the kidney is reviewed and contrasted. The normal ratio of B;U.N. [Blood Urea Nitrogen] to serum creatinine is 10:1 and is usually maintained in chronic progressive renal failure. Clinical situations are reviewed in which the ratio is either considerably greater or less than normal. Data from 9 patients confirm that the B.U.N.: creatinine ratio is increased when prerenal factors cause hemodynamic depression in subjects with otherwise moderate renal impairment, when protein intake or breakdown is excessive, and in certain obstructive uropathies. Data also show that the ratio is decreased in situations of low protein intake, tissue anabolism, liver disease or long-term hemodlalysis. The serum creatinine is the more valid index of the renal function. The ratio of B.U.N. to serum creatinine is of considerable diagnostic value when correctly assessed.