No. It is one of the hallmarks of lupus but not required for a diagnosis. The protein is due to kidney inflammation and damage which isn’t experienced by everyone with lupus

I think that protein in the urine is more linked to lupus nepheritis and not just lupus itself. Im not sure if they diagnose u based off of protein in the urine as i have had that a couple of times, usually they will refer u to see a nephrologist to address possible kidney involvement but protein in urine is not a guarantee that u have lupus.

Yes

Ditto to what JAMS said.

Yes and I also drink a lot of water..