Hi, Mantoux test results must be interpreted from the perspective of patient. An induration of 5 or more millimeters is considered positive in HIV-infected persons A recent contact of a person with TB disease Persons with fibrotic changes on chest radiograph consistent with prior TB Patients with organ transplants Persons who are immunosuppressed for other reasons An induration of 10 or more millimeters is considered positive in Recent immigrants ( Injection drug users Residents and employees of high-risk congregate settings Mycobacteriology laboratory personnel Persons with clinical conditions that place them at high risk Children Infants, children, and adolescents exposed to adults in high-risk categories An induration of 15 or more millimeters is considered positive in any person, including persons with no known risk factors for TB.