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My son had a TB skin test, it came back positive. So we went to his doctor and they did a chest X-ray.  It was clear and normal. Does this mean he is a carrier and does not actually have TB? They put him on medicine to take for 6 months. We are just so confused.


In most cases, a positive TB skin test means that the individual has been exposed or near the TB infection, but does not have the active form of the infection.  Since your child's X-ray was clear, it is likely that the doctor felt that your child had latent tuberculosis infection (similar to a carrier) where the TB infection is sleeping in the body and cannot be transmitted to others.  For persons with latent TB infection, there is a small risk (5-10%) of the infection waking up in the future and causing an active form of the disease.  This is why we give medication while the infection is still asleep. Treatment with isoniazid is very effective at preventing the development of TB in the future.

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Response by:

Catherine A Curley, MD, MS Catherine A Curley, MD, MS
Assistant Professor of Medicine
School of Medicine
Case Western Reserve University