Dunno if youve heard of it, but a number of years ago, there was a company called Theranos, a scam that claimed they could test for all manner of diseases in a short time with just a drop of your blood.

Note that i said “scam” because its obviously BS. Im not familiar with the exact medical capabilities of the tricorder (only ever watched a handful of episodes) but i feel like real next-level medical analysis would come via nano-robots in the bloodstream, not some external device. Then again, its been a couple of years since i heard of advancements in the nano-robot category too.