Urinary Alkaline Phosphatase and LDH Activities in the Differential Diagnosis of Renal Disease

Abstract

Alkaline phosphatase and lactic dehydrogenase (LDH), and substances that inhibit these enzymes are constantly present in human urine. Dialysis removes the inhibitors and permits an accurate and precise defintion of the normal range of urinary enzymatic activities. Small but significant elevations may therefore be detected. In the present study, simultaneous determinations of urinary alkaline phosphatase and LDH activities were performed in 88 patients with renal disease. Certain patterns of urinary alkaline phosphatase and LDH activities emerge from this and previous studies. The activity of both urinary enzymes is normal in renal cysts, calculi, adrenocortical hyper -plasia, prostatic hyperplasia, and benign essential hypertension. An elevated urinary LDH with a normal alkaline phosphatase activity occurs in patients with carcinoma of the bladder, chronic pyelonephritis, sclerosing glomerulonephritis and malignant hypertension. A simultaneous elevation of both activities occurs in renal and prostatic adenocar-cinomas, adrenocortical adenomas and carcinomas, acute glomerulonephritis, membranous glomerulonephritis, lupus nephritis, diabetic glomerulosclerosis, and acute tubular necrosis. The diagnostic sensitivity of elevated urinary enzyme activities permits the detection of early renal and urologic disease before irreversible renal damage or tumor spread has occurred. The majority of patients with potentially fatal renal diseases studied thus far had an elevated urinary LDH activity, whereas the urinary alkaline phosphatase activity was elevated only by certain types of renal disease. Therefore, the simultaneous measurement of both urinary enzymes appears to provide a simple diagnostic pattern of objective alterations to detect, localize, and follow diseases of the kidneys and urinary tract.