I think this might be a “yes, but no” kind of thing.
Yes, these are test strips. Yes, they change color to indicate a reading. Yes, they use chemical reactions to cause that color change.
AFAIK: No, these aren’t for testing blood. No, these don’t seem to be for consumption by an electronic meter. And no, I don’t think this is what OP was asking about.
Like, there’s probably some good info, but not for this thread specifically :P
Source: Pulling it straight out of my ass, but it is informed by my limited experience with medical test equipment, and much less limited experience with electronics.