PPD is considered positive: >= 15 mm Induration: Anybody >= 10 mm induration: Born in a high-revalence country, are in a medically underserved population ( e.g.:Blacks, Hispanics, and Native Americans), individuals with a medical condition that increases risk of TB (e.g.; silicosis, gastrectomy, chronic renal failure, immunosuppressant therapy, malignancy, IV drug abusers, and those that work in the medical field. >=5mm induration: HIV or suspected HIV-positive, close contacts of newly diagnosed TB Cases (everybody on the plane), and abnormal CXR with fibrotic changes suggesting old TB MMWR September 08, 1995/ 44(RR-11);18-34
