I think i have calming news for you
I've been through this all. As i'm working as a pilot, we have to see a doctor once a year to renew our medical license (gives us the permission to fly again).
So 2005 they found protein in my urine sample, and the aviation authorities told me i had to see a kidney specialist. Well, they went as far as taking a sample piece of my kidney, and finally came to conclusion that i have this certain kidney disease, which is very common amongst men of my age (24 at that time). The disease itself doesn't affect my everyday life in any way. Now you shouldn't be worried about the AAS causing you this, i haven't took anything in my whole life and still got this disease, and as i said, it's very common amongst men. One of my classmates from the aviation school also has this, and he hasn't took anything either. Better yet, now almost 4 years later the amount of protein in my urine sample has decreased to almost non-existent
Oh yeah, the kidney specialists very actually laughing when they heard how thoroughly the aviation authorities wanted to investigate my kidneys, as they felt that the reason is really obvious and it has absolutely zero affect in my working capabilities...