<prompt> True statement regarding tuberculine test is -Used for diagnosis of TBMeasures incidence of diseaseMore than 10mm induration in 72 hrs. Indicates positive testMeasures immunity status  <response>: The tuberculin test is the only means of estimating the prevalence of infection in a population . Produce a pale wheal of the skin, 6 to 10 mm in diameter. The result of the test is read after48-98 hrs but 72 hrs3rd day is the ideal. Reaction exceeding 10 mm are considered positive. Ref:PARK;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 23rd edition , Page 185 