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a sterile liquid containing the growth products of, or specific substances extracted from, the tubercle bacillus; used in various forms in the diagnosis of tuberculosis (see tuberculin test).
Old tuberculin a sterile solution of a heat-concentrated filtrate of tubercle bacillus culture grown on a special medium, used for tuberculin tests.
PPD tuberculin (purified protein derivative tuberculin) a sterile solution of a purified protein fraction precipitated from a filtrate of tubercle bacillus culture grown on a special medium, used for tuberculin tests.
tuberculin test any of a large number of skin tests for tuberculosis using a variety of different types of tuberculin and methods of application. The most reliable procedure, now standard, is intradermal injection (the mantoux test) of PPD (purified protein derivative); a positive result consists of a palpable and visible area of erythema and induration greater than 10 mm in diameter developing around the site of injection 48 to 72 hours after the injection. Intermediate strength tuberculin (5 TU) is generally used to test adults; a positive result is virtually diagnostic of a previous or current infection with Mycobacterium tuberculosis. Persons with a negative test are retested with second strength tuberculin (250 TU); in this test a positive reaction is frequently due to atypical mycobacteria infection and is thus nonspecific; a negative result indicates either absence of tuberculosis or the presence of cutaneous anergy due to overwhelming tuberculosis infection or to an associated immunocompromised condition such as HIV infection, Hodgkin's disease, or sarcoidosis.
application of the skin test to the diagnosis of infection by Mycobacterium tuberculosis in which tuberculin or its "purified" protein derivative serves as an antigen (allergen); injection of graduated doses of tuberculin or of purified protein derivative into the skin, most often by means of a needle and syringe (Mantoux test) or by means of tines (tine test); test material may also be applied by means of a "patch" in which it is absorbed but this method (patch test) is considered less reliable; the test is read on the basis of induration and erythema, the former being considered the more diagnostic of infection with the tubercle bacillus (M. tuberculosis); the test does not distinguish between infection in a resistant person without disease and a person with clinical manifestations of disease.
Any of various tests used to determine past or present infection with the tubercle bacillus and based on hypersensitivity to tuberculin.
Etymology: L, tuber + testum, crucible
a test to determine past or present tuberculosis infection based on a positive skin reaction, using one of several methods. A purified protein derivative of tubercle bacilli, called tuberculin, is introduced into the skin by scratch, puncture, or intradermal injection. If a raised, red, or hard zone forms surrounding the tuberculin test site, the person is said to be sensitive to tuberculin, and the test is read as positive. However, a negative tuberculin reaction does not rule out a diagnosis of previous or active tuberculosis. Sputum and gastric cultures, acid-fast staining, and x-ray studies often are needed to establish a diagnosis of tuberculosis. Kinds of tuberculin tests include Heaf test, Mantoux test, Pirquet's test, and tine test.
tu·ber·cu·lin test(tū-bĕr'kyū-lin test)
A dermatologic procedure in which tuberculin or its purified protein derivative (PPD) is injected into the skin; the test is read on the basis of local induration occurring in 48-72 hours.
tuberculin testA skin test used to assess the degree of a person's immunity to TUBERCULOSIS. The result depends mainly on whether the individual has had the usual harmless primary tuberculous infection. A small injection of tuberculin, a substance derived from tubercle bacilli, is injected into the skin (Mantoux test) or pricked in with a multi-needle gun (Heaf test). In positive cases a hard swelling develops in three days. People who react negatively can be given normal immunity by BCG vaccination. A strongly positive reaction may indicate a current tuberculosis infection.
tu·ber·cu·lin test(tū-bĕr'kyū-lin test)
A dermatologic procedure in which tuberculin or its purified protein derivative (PPD) is injected.