Does protein in urine always mean kidney dysfunction?

No: It is possible to have isolated proteinuria in which case there is protein in the urine (no greater than 3g/24h) but no other abnormalities in urine or blood tests, as well as no symptoms associated with kidney problems and a normal physical exam. It is a diagnosis of exclusion.

No: Other causes range from bladder infection to a few percent of people who get protein in the urine just from standing up -- we pick these folks up because the first-voided morning urine has little or no protein.