Positive Tuberculin Skin Tests

What it Means to Have a Positive Tuberculin Skin Test
When TB germs first enter the body, the reaction is often so mild that is causes no illness.

Since there are no "signs" of tuberculosis that can be seen on an x-ray, the infection can be detected only by finding a "positive" tuberculin skin test. This is a slight swelling and redness 2-3 days after injection of a small amount of chemical extract of TB germs (tuberculin) in the skin.

An early tuberculosis infection often does not have any symptoms and is not detected. Its principal importance is the fact that TB germs frequently spread through the blood stream to the top of the lungs and to various other organs during this stage. This can set the stage for the development of tuberculosis years or decades later.

Dormant ("Sleeping") Tuberculosis
Even though the early infection heals, some germs remain alive somewhere in the body, especially in small scars near the top of the lungs. Such germs may remain dormant for years or decades and still "awaken" to cause tuberculosis; just as "dead" roots and bare trees awaken in the spring after being dormant for several months. Dormant TB germs can also be detected in healthy persons by finding a positive tuberculin skin test. We know that about 15 million Americans are infected with TB germs, although most of the infections are in the dormant stage.

Any person who has been exposed to an active case of tuberculosis may have been infected. If the tuberculin skin test is positive, there is no doubt about it: an infection with TB germs has occurred. The development of tuberculosis can be prevented in most persons by taking INH daily as prescribed by the physician.

Prevention of Tuberculosis
One of the greatest advances in tuberculosis today is that by simply taking a dose of INH each morning, as prescribed, the development of tuberculosis can be prevented even though an infection has already occurred. Side effects of INH are uncommon and you may work and lead a normal life while taking it. Occasionally, however, it may cause one or more of the following: loss of appetite, nausea, vomiting, fever, skin rash, muscle aches or even jaundice (yellow color of the whites of the eyes and dark urine). If you develop these symptoms, stop the medication and consult your doctor or clinic nurse

Links
Tuberculosis statistics and information