Stupid question: how do you know whether what is in the vial matches the label at all?

Narrow conclusion, briefly right. Broad conclusion, interestingly wrong. I know which I keep choosing.

Test one thing at a time. It feels slower and it is the only way to learn anything.

“Registered with” is doing an enormous amount of work in that sentence. Not on a travel letter but the pattern is familiar.

Reference ranges differ between labs, so comparing two reports is close to meaningless.