y would someone get a false positive reading on a t.b.test?

Answer 1

Although the tuberculosis skin test is a very valuable test for detecting tuberculosis exposure and infection, sometimes people have a positive TB test result when in fact, they are not infected with Mycobacterium tuberculosis. This is referred to as a false-positive PPD tuberculosis skin test (TST) reaction.

Check out the link for more information:
http://lungdiseases.about.com/od/testingdiagn4/f/false_pos_PPD.htm

Answer 2

Sometimes the test isn't administered correctly... sometimes you have been unknowingly exposed to the disease through the air particles and just didn't get the disease... sometimes your body reacts more strongly to the weakened TB strain than another person would... sometimes your immune system is weak because of another illness/cold and the weakened TB just produces a reaction.... don't worry too much about it... Most places do a 2nd skin test or a chest xray and as long as they are clear you're fine! Good Luck!

Answer 3

Why is this is STD's section?

I used to get it when I was little but I obviously never had t.b. They did that needle test on my arm and the red spot would get bigger and bigger, so my mom, knowing it would happen, always tried to avoid having the test done in fear that they would send me to a t.b. clinic where you could actually get infected with coughing contagious people around!
I've been told it's because of a weak immune system, and that taking certain "prophylactic" meds would prevent it. I never took the drugs, but I also never had another test.