Mantoux test

a test for the presence of a measure of IMMUNITY to TUBERCULOSIS . A PROTEIN called tuberculin, extracted from the TUBERCLE bacilli ( BACTERIA ), is injected in a small quantity beneath the skin of the forearm. If an inflamed patch appears within 18 to 24 hours, it indicates that a measure of immunity is present and that the person has been exposed to tuberculosis. The size of the reaction indicates the severity of the original tuberculosis infection, although it does not mean that the person is actively suffering from the disease at that time.