If it's a blood test it takes 2 weeks for the test results.
There's now saliva testing and that only takes 20 mins to tell the results of it.
I've never used saliva testing before since I wanted a blood test as I was told that they are more accurate and also with blood tests that are checked in a lab they're checked multiple times.
I usually go through my doctor to get tested and I just get it done with bloodwork that I get done yearly.
The only anonymous testing I've done was with those HIV test kits that are sold at drugstores and you prick your finger and collect a blood sample and fed ex it into a lab with a prepaid envelope and a few days later you call and give a code and have the results by phone. The kit costs $60 but you get results very fast, it's a blood test, and it's anonymous.
I hope this helps.