Evaluation of proteinuria

Proteinuria may be the initial manifestation of serious renal disease or merely a laboratory finding of little clinical importance. Excretion of urinary protein in excess of 150 mg per 24 hours in an adult is abnormal. It may be of glomerular, tubular or overflow origin. A comparison of the dipstick and sulfosalicylic acid techniques helps distinguish the source of protein, and electrophoresis is confirmatory. Transient and intermittent proteinuria are not clinically important. Persistent proteinuria requires further investigation.