Interpretation of a tuberculin skin test10
| Tuberculin reaction (mm of induration) | Setting in which reaction is considered significant |
|---|---|
| 5–9 | HIV infection; contact with active contagious case; children with suspected TB disease; other immune suppression (e.g., treatment with TNF-α inhibitors or corticosteroids, chemotherapy, end-stage renal disease) |
| ≥ 10 | All other settings |
Note: TNF = tumour necrosis factor. Administer test intradermally according to guidelines and read in mm of induration at 48–72 h. Test only those patients at risk for TB infection or those with progression of TB infection. Routine testing of individuals at low risk is not indicated. In young children with suspected TB disease, treatment may be started even if the tuberculin reaction result is 0–4 mm of induration.