A healthy asymptomatic adolescent enrolls as a test subject for a research experiment. A bunch of baseline tests are taken, all of which are normal except for mild isolated proteinuria (1g/d). So you ask him to do the following test:
-Discard the first morning void.
-Obtain a 16 hour collection between 7am and 11pm with the patient performing normal activities.
-Obtain a separate 8 hour collection between 11pm and 7am.
While the daytime collection has high urine protein, the overnight collection has 30mg/8 hours.
Challenge: What's the diagnosis?