Can any doctors help me interpret the two step PPD test on my arm?

Question

okay so for nursing school i am required to do a two step PPD test to check for TB. the first one i was fine, there was no hint of anything on my arm. the second one (now a week later) is different, it's hard and raised around the injection site. i read online that this either means that i have had it in my distant past, (which i haven't) or that i am immune to the disorder, but I don't know if that's true?

What is the expected result for the second test? should it be raised or not? is it only an indication of the first injection? Or is this bad news meaning I'll need that chest xray and will be delayed in the fall to begin school :/

(i only got the injection today but the first time it was gone by nighttime completely)

Answer 1

If you got it today - there are no results yet.   The immune system ALWAYS reacts - it reacts in a specific way to TB and another way to just any old break in the skin.

there can be no interpretation until 2-3 days (thursday or friday).

I wouldn't worry about one acting different from the other.

And just as a quick FYI --remember this is just a screening test.  It isn't JUST a hard raised bump that indicates a positive - it is also the SIZE of the bump -- different people can have different positives.   A positive bump in a normal everyday person with no risk factors is much much larger than a positive in a nurse or doctor (or other medical professional).

So I wouldn't worry about it - don't freak out until you know or don't know in 2-3 days.