Hundreds of different ones. Granted you still need some level of medical expertise to be able to accurately interpret results on a lot of them but a smart enough layman could probably self diagnose some illnesses with enough homework.
We even need a prescription for repeat labs. So if my doctor is away for personal reasons for a month and I need to have my [thing that I get tested every month] checked, I can't without having to navigate the entire healthcare system to find a workaround.
I would be easy for me to interpret the results as my doctor is clear that [number] should not fall under [threshold]. It even comes back highlighted in red on the result sheet if it falls under that number. And I have clear instruction on what to do if that happens.
