Isolated asymptomatic proteinuria.

Proteinuria is occasionally detected on "routine" examination (not done for a suspected renal or urinary tract problem) and often presents a diagnostic problem. Even mild proteinuria is abnormal and needs an explanation. Its degree and persistence should be ascertained and associated hematuria looked for. Nonpathological (including orthostatic) proteinuria and renal tubular disorders should be excluded. Persistent proteinuria is mostly due to a primary or secondary (eg hepatitis B) glomerular condition, which requires expert evaluation of renal biopsy. Aggressive therapy may be needed in some cases. The intensity of proteinuria can be decreased with ACE inhibitors. Long-term observation is essential.