1. A glycerin-broth culture of Mycobacterium tuberculosis evaporated to 110 volume at 100°C and filtered; introduced by Robert Koch for the treatment of tuberculosis but now used chiefly for diagnostic tests; originally known as Koch old t. (OT) or Koch original t. 2. One or another of a relatively large number of extracts of Mycobacterium tuberculosis cultures, different from OT and now obsolete.
- purified protein derivative of t. (PPD) purified t. containing the active protein fraction; the t. from which it is prepared differs from t. (1) chiefly in that the bacteria are grown in a synthetic rather than in a broth medium.
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tu·ber·cu·lin t(y)u̇-'bər-kyə-lən n a sterile solution containing the growth products of or specific substances extracted from the tubercle bacillus and used in the diagnosis of tuberculosis see old tuberculin, purified protein derivative
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n.
a protein extract from cultures of tubercle bacilli, used to test whether a person has suffered from or been in contact with tuberculosis. In the Mantoux test a quantity of tuberculin is injected beneath the skin and a patch of inflammation appearing in the next 48-72 hours is regarded as a positive reaction, meaning that a degree of immunity is present.
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tu·ber·cu·lin (too-burґku-lin) [USP] a sterile solution containing growth products of Mycobacterium tuberculosis or M. bovis, used in skin tests for tuberculosis (see tuberculin test, under test) and also a commonly used antigen in laboratory immunology. It is provided as either Old tuberculin or purified protein derivative (PPD) tuberculin.Medical dictionary. 2011.