tuberculin(redirected from Old tuberculin)
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a diagnostic agent used to detect an allergic reaction in individuals infected with tubercle bacilli. It was first discovered by R. Koch.
Several types of tuberculin are produced in the USSR, as follows. Liquid tuberculin, or old tuberculin (OT), is prepared by boiling a bouillon culture of tubercle bacilli. Purified protein derivative of tuberculin (PPD) is prepared by adding to a filtrate of bacilli various chemical substances that precipitate proteins, and then purifying the mixture. Liquid purified protein derivative of tuberculin (PPD-L) is prepared by making standard dilutions of purified protein derivative of tuberculin. The tuberculin test detects the presence of tuberculosis; those persons who react positively should then be vaccinated against the disease. The tuberculin test serves as a means of both early diagnosis and of evaluation of the course of tuberculosis. Only the intracutaneous Mantoux test is in wide use in the USSR.
Veterinaries use the tuberculin test to diagnose tuberculosis in animals. The tuberculin is occasionally injected subcutaneously; more commonly, it is injected intracutaneously or into the conjunctival sac. Animals that react positively are considered tuberculotic. A positive reaction is manifested by inflammatory edema after an intracutaneous injection and by purulent conjunctivitis in the eye test.