<prompt> True about Mantoux test:5 mm always veUsually -ve after treatmentUsually read after 48-72 hoursFalse ve in post measles state  <response>: Ans. is c i.e., Usually read after 48-72 hoursConsidering other choices:a 10 mm is positive and 6-9 mm is EquivocalDoubtful reaction.b It becomes positive after exposure to mycobacterium tuberculosis protein either in the form of infection or immunization and remains positive even after treatment.Note - Tuberculin test in Adults is used as Epidemiological marker and in Children is used as diagnostic marker. 