skin test for immunity

skin test for immunity A method of evaluating whether a person has developed an immune response to a certain infection. A substance is injected into the deep layer of the skin (dermis) and causes a reaction if the immune system recognizes it. One of the most common skin tests is the tuberculin test, which reveals whether a person has been exposed to tuberculosis. The injection is placed on the inside of the forearm, and a positive reaction results in a raised, firm area of skin at the injection site within 2 days.