A good chunk of lab values have different ranges for male vs female.

You've actually hit on a major reason why disclosing isn't as simple as you think it is.

Sure, a good chunk of values have different ranges for male vs female, but the normal ranges for cis folk and trans folk are not the same.

Hormones are the obvious example, but there are large parts of the body that respond to the endocrine profile that we have after hormone replacement. Heart attack symptoms, body fat percentages, resting heart rate, blood oxygen levels, iron levels etc, are all shaped by our hormone profile, not the hormone profiles of cis folk.

That said, I have no idea if those are intrinsic to the sex, or to the hormone levels, so HRT might completely negate or flip those differences.

It entirely depends on the specific medical issue, but in general, it's the latter more often than the former.

I'd run this by your HRT doc.

It's not always that simple. On top of the fact that it's not realistic to see the HRT doc every time you have an unrelated medical issue, the other aspect is, as you're probably aware, sometimes, the patient knows more about their health care needs than the treating doctor, because we need to become experts in a way that a GP does not. If your doctor isn't a specialist in trans care, they're just as likely to give you conservative, incorrect information that was drafted in a time when trans health care even less understood than it is now.

As you're a nursing student, I want to give you some advice. When you are dealing with a patient that isn't "new" to their situation, whether it's trans health care, or long term illness etc, you need to allow for the fact that the patient likely has a lot of lived expertise in dealing with their situation, and broad, general advice is rarely going to be useful to them.