[The usefulness of two-step tuberculin skin testing in nosocomial infection cases].

The usefulness of the two-step tuberculin skin test in the preceding year for the contact investigation was reported, when a pulmonary tuberculosis patient was discovered in our hospital. Four persons showed stronger reaction than the results in two-step tuberculin skin test in the preceding year after nosocomial infection. One of them was diagnosed as pulmonary tuberculosis by chest radiograph, and antituberculosis chemotherapy was started. Other three started chemoprophylaxis. The chemoprophylaxis subjects might increase 4, if basic value of tuberculin reaction had not been available by two-step tuberculin skin test in the previous year. We could identify persons in whom tuberculin reaction became stronger by comparing the test results after exposure with the result of two-step tuberculin skin test in the preceding year. It is considered that two-step tuberculin skin test is very useful to efficiently execute the protective measure.