Cari writes:
I have a question about the PPD / Mantoux TB skin test. About 6 years ago, I got the BCG vaccination. Just a couple of weeks ago, I got the PPD / Mantoux TB skin test for a school physical. The nurse said it was positive because a 16mm bump was present.
My mom said that I tested positive for tuberculosis because I had gotten the BCG six years ago. However, because she didn't have any record of my getting the BCG shot, she had no way of proving it to the doctor.
The doctor gave me a chest x-ray, and it was clear. However, the doctor still put me on antibiotics. He said that I probably had the infection so I have to take Iszonaid for the next nine months.
I also remember that about a year ago, my best friend was sick with a "cold" for 3 months straight. I would try and shield my face whenever she coughed. She said her mom didn't want to take her to the hospital, so she just gave her Robitussin.
I'm really concerned that the doctors are just doing guess work and that I'm taking antibiotics unnecessarily. I really need answers from someone who knows what they're doing - like you.
Dear Cari:
I understand your concern. Your mother could possibly be correct. In my article What is a False-Positive Tuberculosis Skin Test?, I discuss the effects of the BCG vaccination. Here is an excerpt from that article:
Although the tuberculosis skin test is a very valuable test for detecting tuberculosis exposure and infection, sometimes people have a positive test result when in fact, they are not infected with M. tuberculosis. This is referred to as a false-positive PPD tuberculin skin test reaction.
False-positive reactions to the tuberculosis skin test typically occur because of:
However, this is not always the case. It is very important that you follow your doctor's orders and take the medication as prescribed, so as to avoid developing multidrug-resistant tuberculosis. If you believe your doctor has made an error, you can always get a second opinion.
It is not uncommon for a person to test positive for tuberculosis, have a clear chest x-ray, yet be prescribed antibiotics. This is a precautionary method that the healthcare profession uses to avoid a tuberculosis outbreak.
