Induration ≥5 mm: Patients with HIV infection

recent close contact to person with known active tuberculosis (TB), patients with chest x-ray consistent with prior TB,

patients with organ transplants and other immunosuppressed patients (receiving the equivalent of prednisone ≥15 mg/day for ≥1 month or those taking TNF-α antagonists).

Induration ≥10 mm: Patients with clinical conditions that increase risk of TB infection,

people born in countries where TB disease is common,

IV drug users, residents and employees of high-risk congregate settings,

Mycobacte-riologylaboratory workers,

people <90% of ideal body weight,

children <5 years of age, or infants, children, and adolescents exposed to adults at high risk

Induration ≥15 mm: Patients who do not meet any of the above criteria (no risk factors for TB)