Is this TB

[omega30]

My husband recently took the TB QuantiFERON® test and it came back positive. He is from India but he has no symptoms of any infection. We recently took a CT scan of the chest to rule out sarcoidosis and nothing abnormal was found in the lungs.

He has had the BCG vaccine back home in India and we dont know if that can produce a positive test result. He has taken his chest x-ray today and is scheduled to meet an infection specialist doctor but I am trying to gather as much information as possible.

Even if his x-ray result comes out clear, will he be considered to have the latent TB.

Thanks

[mkh9]

You are welcome. Glad to help. That is a high result. Good that you are going to see an infectious disease doctor. Let me know how it goes.
take care,
mkh9

[omega30]

Hi mkh9,

Thank you so much for asking your friends and for getting back to me on this. My husband's results was > 10 IU/mL

We will make an appointment with an infection specialist.

Thanks again.

[mkh9]

So I talked to one of my friends and she explained the test better to me. There are some false positives but not as high as you think. But, in any case this is the scenario.
So, because your father was positive on the quantiferon gold test it means he was exposed to TB and it is in his system, so that means he has a latent infection, especially since it was confirmed that his Xray was negative (provided there is no false positive). The BCG vaccine does not interfere with the Quantiferon gold test. If the test was very low positive (0.35) or so you could repeat it in 6 months or if you are worried about the false positive. But if it was high positive , around 10 or 12 (not on the boarderline) he probably was exposed especially since he is in an area (India) where there is a high prevalence of TB. Now not all people get TB just because you are exposed. But the problem is when you get older you eventually get run down or immunocompromised and the TB can take over your immunity and give you an active infection. So, he can take INH (isoniazid) as a preventive but it is for about 8-9 months. It is up to him and you to decide whether or not to take this treatment. If he gets TB he will have to take 4 harsher antibiotics for about 3 months and stay on them no matter what or he can develop resistant TB. So it is really up to you. These are the options.
hope this helps.
mkh9

[mkh9]

One person wants to know what was the size of the quantiferon gold reading? How many millimeters in diameter or what the reading they got when they read it?
thanks,
mkh9

[mkh9]

Usually, although there are cases where it can start in the spine or other places. The majority are in the lung. I haven't heard back from them. I don't know if anyone else will write. It seems like some group are out of town. You may not ever know 100% as they base it on country of birth, whether the TST skin test was positive , whether there and symptoms,  if it was country of high incidence of  TB, if the quantiferon gold test was positive and Xray. He has only one of these where probably was in a country of high prevalence (India) but the rest have come out negative. The TST we won't know the true answer probably. Since a lot of strains of TB are now resistant to INH (Isoniazid) which used to be the drug they gave if you were exposed but were not actively infected they probabably can't give this anymore or if they do it may not be effective. That is why they give 4 antibiotics now when they treat for active infections. I'm not sure what the preventive med(s) are now or if they still use INH. I can still wait to see if I hear any more information my friends. It is up to you. I don't mind waiting to see if anyone else writes.
mkh9

[omega30]

Thank you mkhg for following up with your colleagues. I truly appreciate it. My husband has had the BCG vaccine.

Is it true that TB always starts infecting the lungs and then may spread to other parts such as the bones.

[mkh9]

I'm still looking into this. I asked a colleague and he said you can do the PPD skin test or regular TST but if you had the BCG vaccine then you will always have a false positive. But it does check for latent TB. The question I have to find out is if you have the BCG vaccine what the interpretation would be compared to a positive. If it is different (which it may be) then it would be helpful. I'll let you know if I get an answer.
mkh9

[mkh9]

I don't think you can discriminate between the latent and false positive in this test. But there may be another test. I have asked some colleagues by email. I'll get back to you.
mkh9

[omega30]

Thanks for your response. The x-ray came back negative. And he doesn't believe he has had TB in the past. We were researching and found that the false positive rate for the quantiferon gold test is 30%

How do we know if he came under the false positive or if he really has latent TB.

[mkh9]

Firstly, the BCG test cannot produce a positive test with the QuantiFERON test. But the test can pick up past exposure to TB and active disease. So the Xray will determine if it is active or latent (past exposure). If he has past exposure you still may want to take the INH part of the treatment or whatever the current preventive treatment is. Because if he becomes immunocompromised he can come down with the disease at some point. So since the CT was negative it probably is negative. But they weren't looking for that. So, I would wait for the Xray just to make sure and then you can know if it is active or latent by that final Xray. If active then of course he would need treatment with 4 antibiotics for about 2-3 months. Hope this helps.