What does a positive skin test mean?
A person with a positive skin test has been exposed to someone with active TB disease and has become infected. The infection can remain in the body without causing symptoms of illness. A strong immune system keeps the bacteria walled-off or inactive. As long as the infection remains inactive, the person is not considered contagious. Without preventive treatment, this inactive infection can lead to active disease over time. This is especially true if the immune system is weakened with illness or other stresses. What is preventive treatment? The goal of preventive treatment is to kill the walled-off or inactive infection. This decreases the chance of the infection becoming active in the future. The usual treatment is an antibiotic called INH (isoniazid). This medicine is taken daily for six months for most adults and is relatively inexpensive. The most common side effect is stomach upset. It can be taken with food to reduce this problem. Less often, INH can cause numbness or tingling of
A positive skin prick tests confirms the presence of IgE to the test allergen. IT IS IMPORTANT TO NOTE THAT THE DETECTION OF IgE ANTIBODIES TO AN ALLERGEN DOES NOT NECESSARILY MEAN THAT ALLERGEN IS CAUSING ANY SYMPTOMS: THESE TESTS HELP WITH DIAGNOSIS WHICH MUST INCLUDE A CAREFUL HISTORY. Some patients have very sensitive skin and can show reactions that are not due the allergen: such false positive skin tests are controlled for by also testing with a negative control solution (salt water). What does a negative skin test mean? Generally, a negative skin tests excludes the presence of IgE to the test allergen and rules that allergen out as a cause of allergic symptoms. However some patients will not show a reaction on skin prick testing (false negative, for example if they have taken antihistamine tablets or some antidepressant medications. What happens during the skin testing and does it hurt? You will be asked to stop any antihistamine medication for 48 hours before the test. Dependin
A positive skin test means that you have antibodies against the germ that causes tuberculosis. Your infection can be latent (without any symptoms) or it can develop into disease if untreated. A positive test does not mean you have active disease. Other tests (such as a chest x-ray and sputum test) are needed to determine this.
If a skin test shows a certain amount of swelling 48-72 hours after placement, this is called a “positive” skin test. This may indicate that TB infection has occurred and further tests need to be done to determine the status of the TB infection. All persons with a positive skin test should have both a chest x-ray and an evaluation of possible symptoms of active TB. Are there any reasons not to be tested for TB? Any person with a documented history of a positive skin test should not be tested. TB skin testing can be done for persons who have been vaccinated with BCG. Studies indicate that a positive TB skin test in a person with a history of BCG vaccination is more likely to be due to TB infection than as a result of the BCG. Some conditions may necessitate a delay in testing or special testing. Please tell the nurse if you have any of the following: severe illness with a fever, certain viral infections, Hodgkin’s disease, Sarcoidosis, vaccination within the past 6 weeks with a live vir
