Is 382 ng/dl low for total testosterone?

Pretty much the title. P.A said that my testosterone was low which isn’t too uncommon for my age (18 y/o male) My understanding is that 382 is within the reference range and that testosterone levels vary greatly between individuals so a number on a lab test doesn’t tell you much. I have no symptoms or complaints and this was part of the practice’s new patient screening process, and they measured other things like cholesterol and b12. Am I incorrect in my understanding? If I am correct it seems pretty terrible that this person is telling young men (or people in general) they have low T when that isn’t necessarily the case.

Your understanding is generally correct.

If you have no symptoms or complaints, this should have never been measured at all (likewise with B12, and likely some other tests you underwent too). I have suspicions about this clinic’s “new patient screening process”.