Screening for Latent Tuberculosis (2024)

• ¹Associate Editor, JAMA

Español

Tuberculosis (TB) is an infection that most commonly affects the lungs but that can also involve other parts of the body.

Tuberculosis is classified into 2 types: latent TB and active TB. Active TB is highly contagious and is spread through the air. Symptoms of active TB include cough (sometimes with blood), fever, and weight loss. Latent TB, on the other hand, causes no symptoms and cannot be spread to others because the body’s immune system has “walled off” the infection, keeping the bacteria inactive. However, latent TB can turn into active TB at any time. This may occur when the body’s immune system is weakened due to either illness or certain medications.

Finding and treating latent TB with medications can rid the body of the infection before it becomes active TB.

Screening for latent TB is done in 2 ways:

• A tuberculin skin test, in which a substance is injected under the skin. Two or 3 days after this injection, a clinician looks for development of a bump at the injection site, which may be a sign of latent TB.

• A blood test called an interferon-gamma release assay that detects the body’s immune response against TB. This is a 1-time test that does not require a return visit.

The term screening means looking for a condition or illness in individuals who do not have specific symptoms or concerns related to that illness. One might naturally presume that screening would be beneficial, but the reality is that sometimes looking for problems when there are no symptoms can turn out to be harmful. Therefore, it is important to carefully weigh the pros and cons of screening.

Pros of screening include earlier detection of latent TB, which leads to earlier treatment with medication. Treatment of latent TB eradicates it from the body and prevents it from becoming active TB. There is good evidence that treatment of latent TB decreases rates of active TB.

Cons of screening include false-positive findings that lead to unnecessary treatment. The treatment course is long and can sometimes carry a stigma. There are also potential side effects of medications, particularly in the liver.

Tuberculosis is rare in the US. Because of this, when considering the population as a whole, the pros of screening do not necessarily outweigh the cons. However, if you are at higher risk for TB exposure, you may benefit from screening. You may be at higher risk if you

• were born in or have lived in countries with high rates of TB. An up-to-date map of these countries can be found here. In the US, the majority of active TB infections occur in people from Mexico, the Philippines, India, Vietnam, and China.

• live in high-risk settings of close contact with others, such as homeless shelters or correctional facilities.

• have a weakened immune system from either illness or certain medications.

The US Preventive Services Task Force (USPSTF) recommends screening for latent TB in persons at increased risk for TB infection.

The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be downloaded or photocopied noncommercially by physicians and other health care professionals to share with patients. To purchase bulk reprints, email reprints@jamanetwork.com.

Conflict of Interest Disclosures: None reported.

Source: US Preventive Services Task Force. Screening for latent tuberculosis infection in adults: US Preventive Services Task Force recommendation statement. JAMA. Published May 2, 2023. doi:10.1001/jama.2023.4899

See More About

Citation

Jin J. Screening for Latent Tuberculosis. JAMA. 2023;329(17):1526. doi:10.1001/jama.2023.6495

Manage citations:

© 2024