Targeted testing is a TB control strategy used to identify and treat persons:
At high risk for infection with M. tuberculosis
At high risk for developing TB disease once infected with M. tuberculosis

Identifying persons with LTBI is an important goal of TB elimination because LTBI treatment can:
Prevent the development of TB disease
Stop the spread of TB

High-Risk Groups
High-risk groups can be divided into two categories:
People who are at high risk for becoming infected with M. tuberculosis
People who are at high risk for developing TB disease once infected with M. tuberculosis

High-Risk Groups for TB Infection
Close contacts of people known or suspected to have TB
People who have come to U.S. within 5 years from areas where TB is common
Low-income groups
People who inject drugs
People who live or work in high-risk settings
HCWs who serve high-risk clients
Racial or ethnic minority populations
Infants, children, and adolescents exposed to adults in high-risk groups
People living with HIV
People recently infected with M. tuberculosis (within past 2 years)
People with certain medical conditions known to increase risk for TB
People who inject drugs
Infants and children younger than 4 years old

Diagnosis of Latent TB Infection (LTBI)
Available testing methods for M. tuberculosis infection:
Mantoux tuberculin skin test (TST)
Blood tests known as interferon-gamma release assays (IGRAs):
QuantiFERON®-TB Gold test (QFT-G)
QuantiFERON®-TB Gold In-Tube (QFT-GIT)

Mantoux Tuberculin Skin Test_Administering the Test
TST is administered by injection
Tuberculin is made from proteins derived from inactive tubercle bacilli
Most people who have TB infection will have a reaction at injection site
0.1 ml of 5 tuberculin units of liquid tuberculin are injected between the layers of skin on forearm
Forearm should be examined within 48 - 72 hours by HCW
Reaction is an area of induration (swelling) around injection site
Induration is measured in millimeters
Erythema (redness) is not measured

Mantoux Tuberculin Skin Test_Interpreting the Reaction
Induration of > 5 mm is considered positive for:
People living with HIV
Recent close contacts of people with infectious TB
People with chest x-ray findings suggestive of previous TB disease
People with organ transplants
Other immunosuppressed patients

Induration of > 10 mm is considered a positive reaction for:
People who have recently come to U.S. from areas where TB is common
People who inject drugs
People who live or work in high-risk congregate settings
Mycobacteriology laboratory workers
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