TB screening updates
The U.S. Preventive Services Task Force (USPSTF) released in September a final recommendation statement on TB screening for latent tuberculosis infection (LTBI) in adults.
The USPSTF recommends screening among adults who are at increased risk of tuberculosis, but who do not have symptoms. This recommendation does not apply to adults with symptoms of tuberculosis or to children and adolescents. The independent, volunteer panel of national health experts has given this recommendation a grade B, meaning it is highly certain screening offers a moderate benefit, or moderately certain screening offers a moderate-to-substantial benefit.
This recommendation is in line with the recommendations of others. The CDC identifies persons at risk for developing tuberculosis as those who have an increased likelihood of exposure to persons with tuberculosis disease, or persons with clinical conditions or other factors associated with an increased risk of progression from LTBI to tuberculosis disease (HIV infection, injection drug use, radiographic evidence of prior healed tuberculosis, low body weight, or other medical conditions).
Although Latent Tuberculosis(LTBI) is asymptomatic, signs and symptoms of active tuberculosis disease may include cough (R05), hemoptysis (R04.2), abnormal weight loss (R63.4), night sweats (R61), fever (R50.9), and shortness of breath (R06.02). Note that signs or symptoms routinely associated with tuberculosis should not be assigned in addition to a confirmed diagnosis of the disease (ICD-10 category A15 ? A19).
Two types of screening tests for LTBI are currently available in the United States:
- Mantoux tuberculin skin test (TST) (CPT(R) 86580Skin text; tuberculosis, intradermal)
- Interferon-gamma release assays (IGRAs) (CPT(R) 86480Tuberculosis test, cell medicated immunity antigen response measurement; gamma interferon)
The skin test reaction is measured in millimeters of the ?induration? after 48 to 72 hours.
IGRAs require a single blood sample and laboratory processing within 8 to 30 hours after collection. Two types of IGRAs are currently approved by the FDA:
- T-SPOT.TB (Oxford Immunotec Global)
- QuantiFERON-TB Gold In-Tube (Qiagen)
Generally, the CDC recommends screening with either the TST or IGRA, but not both.
The USPSTF found no evidence on the optimal frequency of screening for LTBI. Depending on specific risk factors, screening frequency could range from one time only screening among persons who are at low risk for future tuberculosis exposure, to annual screening among those who are at continued risk of exposure.