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Tuberculosis

Scared and needing some advice

11/26/2007

Question:

I went into the E.R. and was diagnosed with Kidney Stones. Among that an X-Ray showed some Nodules in my lungs. They conclude it may be Tuberculosis. They did the skin test. Nothing on my left arm has come about. However my right arm, A very very small redness has occurred. It is nothing like the pictures I have seen online for the Positive skin test. It is maybe a little larger than a BB for a bb gun. It does not seem raised or bumpy.

Should I worry and stress about this? Tomorrow I go for results. I currently have hepatitis b as well. So I`m scared. I have a family I must provide for. Should I be worried?

Answer:

Redness alone is not sufficient to determine whether a PPD is positive and latent tuberculosis is present. The most important and reliable factor is the size of induration (swelling that is palpated or felt) of the PPD site 48-72 hours following intradermal injection onto the right arm. In the past, medical providers used to place "controls" onto the left arm. These controls were intradermal injections of organisms that the majority of us are exposed to many times throughout our lifetime. Such controls were supposed to create an area of induration on the left arm. If the controls were positive and the PPD was negative, that would suggest that the patient did not have latent tuberculosis. If the controls and the PPD were negative, that would suggest that the patient might be anergic -- their immune system was not responding appropriately to the foreign organisms and the PPD was a false negative.

Unfortunately, the control testing is not reliable. As a result, controls are not generally used to determine whether the PPD result is valid. If the PPD is negative, but your health practitioners remain concerned about you having tuberculosis, they should obtain sputum specimens from you. One sputum first thing in the morning on waking for three days is sufficient. Alternatively, a single induced sputum performed by a trained respiratory specialist, or a bronchoscopy performed by a pulmonologist are suitable replacements.

For more information:

Go to the Tuberculosis health topic, where you can:

Response by:

J Daryl   Thornton, MD, MPH J Daryl Thornton, MD, MPH
Assistant Professor of Medicine
School of Medicine
Case Western Reserve University