TB skin test/positive

[GingerSue]

how is the area of induration determined?

The way mine was read today, the nurse used her pen to gently push one side of the reddened area (which she marked on my skin), and then she used the pen to push on the other side of the reddened area, marked the skin, and measured between the two lines.

Is this the usual way of measuring the induration?

She did say that I am not to have any more skin tests, and that if I do, then the area could become larger.

I had a BCG back in the 70s, and I had a skin test in 1998/99. Is it possible that this week's skin test was one of those skin tests that I need not have had, one of those that became larger?

I'll be going for chest x-ray.

[ShaunES]

A BCG vaccination will almost always give a false positive PPD.

You won't be getting any more PPD tests, and if they ask you to have one, refuse and get a CXR (in future).

I've no experience with measuring induration, but it does sound like an accurate way to do it.

[suzanne4, RN]

Some new policies have come out in the US concerning the BCG that is given overseas to children:

The expected time that the person should give a positive Mantoux test based on that vaccine is less than twenty years, you should not remain positive forever from it. So now, when someone that received the BCG and has come to the US years later, and have a positive PPD, they are usually treated as they are considered having been in contact with someone that was positive and developed antibodies because of that.

The countries where you saw BCG predominantly used have had higher incidences of TB in the first place.

Just because you have had a positive PPD, it does not mean that you have the disease, just that you have been exposed to it. You will need to get a chest x-ray to follow up to this, and then your physician will decide if you need to be treated or not. You may wish to follow up with an infectious disease physician to get the latest information to help you make an informed decision.

You may also wish to check out the International Forum, this topic comes up regularly there.

[Elvish, BSN, DNP, RN, NP]

Some new policies have come out in the US concerning the BCG that is given overseas to children:

The expected time that the person should give a positive Mantoux test based on that vaccine is less than twenty years, you should not remain positive forever from it. So now, when someone that received the BCG and has come to the US years later, and have a positive PPD, they are usually treated as they are considered having been in contact with someone that was positive and developed antibodies because of that.

The countries where you saw BCG predominantly used have had higher incidences of TB in the first place.

I used to work in a community health center where 99% of our patients were from developing countries & who had received the BCG. We also did immigration physicals (PPD is a requirement) for people from countries all over the world where BCG is given.

I have seen MANY MANY people with a hx of BCG whose PPDs were just as flat as mine; some were children who had received the BCG within recent history. So I will have to respectfully disagree with Shaun, though his/her clinical experience may be different than my own. (no hard feelings, ok?)

Thanks for posting the above, suzanne. You beat me to it.

I have measured many a +PPD and I did it the same way yours was done, GingerSue. What constitutes positive depends on your situation. But do get your CXR if it's recommended...just in case.

Something anecdotal: I have seen several cases where someone will have a +PPD one year, then forget and have one placed the next (I know, how do you forget....) that turns up neg. Go figure.