Bad reaction to TB skin test?

[J&N* 68]

I recently had to do my medical examination for AOS (after they lost mine) and I got a TB skin test, after 2 days it started to be a little pink and form a small bump where the needle was, it wasn't itchy or red or even big, the doctor said it is a negative, and I had a chest X-ray before in my first medical exam and it was also negative. I just don't understand why did I react to it?? Has anyone reacted to the test before even though it was a negative??

[Dakine10 5,452]

I recently had to do my medical examination for AOS (after they lost mine) and I got a TB skin test, after 2 days it started to be a little pink and form a small bump where the needle was, it wasn't itchy or red or even big, the doctor said it is a negative, and I had a chest X-ray before in my first medical exam and it was also negative. I just don't understand why did I react to it?? Has anyone reacted to the test before even though it was a negative??

A positive reaction has to exceed a certain size (14mm in diameter if I remember correctly). The measurement has to be taken after 48 hours at the earliest.

It's common to have redness and swelling. It can often be larger then 14mm the first day. This is due to inflamation at the injection site and/or irritation from the PPD components. The important thing is the size of the reaction after 48-72 hours.

[Flames9_RN 358]

Depending on the situation, as small as 5mm can mean a + test. If one has had the BCG vaccine in the past, it could result in a + test as well.

http://www.medicinenet.com/tuberculosis_skin_test_ppd_skin_test/page2.htm

[Dakine10 5,452]

Depending on the situation, as small as 5mm can mean a + test. If one has had the BCG vaccine in the past, it could result in a + test as well.

http://www.medicinenet.com/tuberculosis_skin_test_ppd_skin_test/page2.htm

That's true, but the OP had a negative test, not a positive. I would hope the MD considered any relevant medical history when interpreting the test. In any event having a "reaction" to the test is not the same as having a positive test. The OP had a reaction and a negative test, which is a fairly common occurrence.

Edited March 26, 2011 by Dakine10

[Flames9_RN 358]

Thats is correct.More so just providing her a link for info.

[J&N* 68]

Thanks everyone!! I know I'm okay but just didn't get why I reacted to the test!

[faithinGod 8]

Thanks everyone!! I know I'm okay but just didn't get why I reacted to the test!

Hi Junita,

the shot that you took for the test containe proteins of Micobacterium Tuberculosis, the bacteria that causes TB, the reason why you had a slight reaction was because you do have some antibodies against MT probably from prior BCG vaccination and they reacted by attacking the injected proteins in the shot, called PPD.

A positve reaction is when the area is hard,indurated, elevated and over 15mm, even smaller in people with some other severe ilnesses or special conditions.

You don`t need to worry, most people get that slight reaction.

Oh, i called you Junita, didnt see you changed your name ,oops , sorry

Edited March 26, 2011 by faithinGod

[J&N* 68]

Hi Junita,

the shot that you took for the test containe proteins of Micobacterium Tuberculosis, the bacteria that causes TB, the reason why you had a slight reaction was because you do have some antibodies against MT probably from prior BCG vaccination and they reacted by attacking the injected proteins in the shot, called PPD.

A positve reaction is when the area is hard,indurated, elevated and over 15mm, even smaller in people with some other severe ilnesses or special conditions.

You don`t need to worry, most people get that slight reaction.

Oh, i called you Junita, didnt see you changed your name ,oops , sorry

Thanks a lot faithinGod, I actually noticed that the swelling is going down and it's even less pink now, thank God! It's all good!

Edited March 26, 2011 by Nermeen&Joe

[faithinGod 8]

Thanks a lot faithinGod, I actually noticed that the swelling is going done and it's even less pink now, thank God! It's all good!

[Anna C. 4]

As mentioned, BCG (vaccine for TB) can result in a reaction, but usually the vaccine is given at birth and wears off around 18-20 years. I had it at birth and my skin test didn't have the slightest reaction (at 24 years). Now if you have two skin tests within a year the second test can result in a false positive. The doc told me that... there also is a blood test called quantiferon that easily shows whether a person has TB or not, and it is cheap an you dontr have to come back ($40);

[Amby 490]

you could be allergic to the preservative

Edited March 26, 2011 by Amby