Saturday, January 17, 2009

PPD Test and the BCG vaccine

This shows a positive PPD test result (a red swollen with 2mm diameter)
Here in the United States, health care providers uses a simple skin test called the PPD (purified protein derivative) to test for exposure to tuberculosis. This procedure is done by injecting the tuberculosis germ under the skin and if there is an induration or swelling, hardness or firmness of the skin, then you are positive. Unlike in the Philippines where they normally uses Chest xray for pre-employment requirements, here they require you to have a PPD test. When the hospital hired me, they required me to have a PPD test, and I was positive. I was scared of course, I've been exposed to a lot of TB patients back home, and I know that being exposed to a person with an active TB, you can have their infection too, you will not aware you've got it because your immune is strong. It is called an inactive TB in your system. The germ is already in your body but not yet causing disease. This is the scenario that I thought I have when I was positive for a PPD test.

My employer scheduled me for a chest x-ray just to make sure if I have an active pulmonary tuberculosis, but the result was negative. The nurse asked me if I had a BCG vaccine , and I said yes I did, but I am not sure when. I showed her my vaccine scars on my shoulder. Then she told me maybe that's the reason why I am PPD positive, due to the vaccine itself rather than from exposure to the germ. I learned that BCG vaccine is not common or not available here. If you had BCG vaccine before then more likely, you will get a positive result. If your an immigrant, and your employer asked you to have a PPD test done, just let them know you had a BCG vaccine before, they may not let you do the test anymore.

4 comments:

Unknown said...

Thank you for this text and a photo.

Unknown said...

It is really important for you to know that the BCG vaccine only gives a positive PPD within the first 3 years of getting it- 5 max. EVERYONE, including people who have been vaccinated (as the BCG vaccine has not been proven to be effective beyond five years) needs to get a PPD, and a follow up chest xray if positive (to see if active). It is a common misconception that the BCG gives a positive ppd. If you have a positive PPD you could be a carrier of latent TB (not yet active).

Gigi said...

@Uzurov, you are welcome thanks for reading my post :)

@Lucrecia, thank you for informative comments.

Anonymous said...

what if -PPD but with residual fibrosis on the x-ray?