The first day I joined a martial arts class was very humbling. I was asked to to spar with a senior. For a good 15 minutes I tried to hit him. I mean I really tried, and to no avail. I distinctly remember thinking how easy it would be to punch the senior, and could not understand why I could not hit him. Between that and doing pushups until failure. I really did not want to go back. I did, and stuck with it, but that really was a reality check for me.
There isn't as far as I can tell, perhaps quest diagnostics might have something, but what's so interesting is how fundamental blood work like a CBC is in diagnosing and monitoring any disease or health conditions.