What could this mean, if a few years ago I had a TB test, tested negative, and then just a few weeks ago, tested positive for TB. I know I am immunized against TB but I find it quite odd that I was tested positive when previously I had tested negative.
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21) False positive from your vaccination, 2) you were exposed to TB at some time between your first TB test and your more recent one.– Carey Gregory ♦Commented Mar 18, 2017 at 16:52
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1 Answer
You don't specify which test was used to screen for TB, in this answer I will assume that Mantoux test was used.
You probably were vaccinated using Calmette-Guérin vaccine. Unfortunately this has been proven not to give an efficacious immunity against TB infection.
In this scenario there are two chances:
- You actually were exposed to M.Tuberculosis.
- The Mantoux test is probably a false positive due to your vaccination if you are at low risk for TB infection or to other factors.
Being at low risk means an individual was not:
- In contact with another person with infectious TB
- Born or has lived in a high TB prevalence country
- Continually exposed to populations where TB prevalence is high
In both cases I would personally advise you to contact a doctor to get a chest x-ray and a IGRA quantiferon blood test to further investigate. This is particularly advisable in your case having two different outcomes from serial testing which honestly could increase the possibility of latent TB.
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Thanks for the answer. I had a chest x-ray done but the doctors indicated it was more likely it was exposure to someone who had TB and not I who had TB> Commented Mar 19, 2017 at 18:49
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You should seek consulence from a specialist who can prescribe a IGRA quantiferon test and if it confirms the diagnosis of latent tuberculosis you should begin treatment for the condition.– KingBOBCommented Mar 21, 2017 at 20:52