Albuminuria vs urinary total protein for detecting chronic renal disorders

A literature review and our own data are presented to demonstrate that urinary albumin (UA) excretion increases in many renal disorders and that it offers a far more sensitive indicator than the commonly used urinary total protein (UTP) for the early detection of renal involvement in many chronic diseases such as diabetes mellitus, hypertension, and systemic lupus erythematosus. In many individuals with these disorders, UA increases severalfold, even while UTP remains within the reference interval. UA is also more suited than UTP for following therapeutic responses in these slowly progressive renal disorders. Increases in UA are associated with increased mortality. UTP measurements are plagued with many analytical problems, whereas UA is much easier to standardize. We recommend that both UA and UTP be measured when quantitative urine protein assays are ordered, especially when the UTP is less than 300 mg/g of creatinine.