- Human immunodeficiency virus (HIV)-positive persons
- Recent contacts 1 of Tuberculosis (TB) case patients
- Fibrotic changes on chest radiograph consistent with prior TB
- Patients with organ transplants and other immunosuppressed patients (receiving the equivalent of > 15 mg/d of prednisone for 1 mo. or more)
> 10 mm considered positive for:
- Recent immigrant (i.e. within the last 5 years) from high prevalence countries
- Injecting drug users
- Residents and employees 2 of the following high-risk congregate settings: prisons and jails, nursing homes and other long term care facilities for the elderly, hospitals and other health-care facilities, residential facilities for patients with acquired immunodeficiency syndrome (AIDS) and homeless shelters
- Mycobacteria laboratory personnel
- Persons with the following clinical conditions that place them at high risk: silicosis, diabetes mellitus, chronic renal failure, some hematologic disorders (e.g. leukemias and lymphomas) other specific malignancies (e.g., carcinoma of the head, or neck and lungs), weight loss of > 10% of ideal body weight, gastrectomy, jejunoileal bypass
- Children younger than 4 years of age or infants, children and adolescents exposed to adults at high-risk
> 15 mm considered positive for:
- Persons with no risk factors for TB
TST Conversion: An increase in reaction of >10 mm within 2 years should be considered a TST conversion indicative of recent infection with M.tb. infection.
1 Recent contacts are individuals who have shared air for a prolonged period of time with someone who has infectious M.tb (from hours to months depending on the circumstances).
2 For persons who are otherwise at low risk and are tested at the start of employment a reaction of >15 mm induration is considered positive.
Reference: American Thoracic Society, Centers for Disease Control. 2000. Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection. American Journal of Respiratory Critical Care Medicine. Vol. 161, No. 4, Part 2.