Hi, I am Dr Mbong.
Interesting question. If your treatment was successful and you are free from PTB, then your IGRA test will be negative. The test wouldnt show a history of disease.
If it is positive, then you have been re-infected or are having a relapse even if you have no symptoms (what is called the latent form of the disease which is characterised by the absence of symptoms but the germ is in your body and waiting for an opportunity to manifest).
Once you have got PTB once, even after treatment and without re-exposure to the germ, the disease can relapse (due to some few germs that stay hidden in your body & escape medication action), if your immune system wanes due to stress
, poor nutrition, steroid
or other immuno-suppressant drug use or if you develop an immuno-suppressive disease like HIV
, cancer, etc. So make sure you keep in good health.
Best regards, Dr Mbong