Tuberculosis Screening and Testing of U.S. Health Care Workers: 2019 Recommendations

These are the recommendations as published in 2019.

CDC's 2005 guidelines on preventing tuberculosis (TB) transmission in health care settings called for baseline TB screening of all U.S. health care personnel and annual testing for those in medium-risk settings or where transmission might be ongoing. In 2019 a work group of the National Tuberculosis Controllers Association (NTCA) and CDC updated those recommendations.

Why change

Health care workers were once at higher risk of latent TB infection (LTBI) and TB disease from their work, but that may no longer be true.

• The U.S. TB rate fell to 2.8 per 100,000 people in 2017, 73% below 1991 (10.4) and 42% below 2005 (4.8).
• From 1995 to 2007, TB rates among health care workers were similar to those in the general population, raising doubts about whether routine repeat testing was worth its cost.
• A study of about 40,000 health care workers at a U.S. medical center in a low-incidence state found only 0.3% converted to a positive skin test from 1998 to 2014, and few of those conversions were due to work.
• Both interferon-gamma release assays (IGRAs) and tuberculin skin tests (TSTs) have well-known limits when used repeatedly in people at low risk.

The evidence review

Formed in 2015, the work group included experts in TB, infection control and occupational health from CDC, state and local health departments, universities and occupational health associations. In 2017 it reviewed studies published from January 2006 to November 2017 on TB screening and testing of health care workers in high-income, low-incidence countries. Of 1,147 citations, 36 studies qualified: 16 from the United States, 17 from Europe and one each from Australia, Israel and New Zealand; 34 were in hospitals. Results varied widely.

For U.S. health care workers, the pooled findings were:

Among 63,975 U.S. health care workers in eight studies reporting disease, none developed TB disease.

The draft recommendations were presented in 2018 to the Advisory Council on the Elimination of Tuberculosis (ACET), the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the National Tuberculosis Conference. ACET commenters said encouraging treatment of LTBI could save money and help eliminate TB; HICPAC commenters supported less testing but asked about evidence and feasibility; and all encouraged a companion guide to help facilities put the changes into practice, which NTCA expected to finish in 2019.

The six updated recommendations

1. Baseline screening for all health care personnel before placement, including an individual risk assessment and symptom evaluation.
2. Baseline testing with an IGRA or TST for anyone without documented prior TB disease or LTBI.
3. No routine repeat testing at any interval after baseline, such as annually, unless there is a known exposure or ongoing transmission.
4. Treatment encouraged for all health care personnel with untreated LTBI, unless there is a reason not to.
5. Yearly symptom screening for health care personnel with untreated LTBI.
6. Yearly TB education for all health care personnel.

Parts of the 2005 guidelines outside screening, testing, treatment and education, such as facility risk assessments that guide infection control, are unchanged. The update does not address when to choose an IGRA over a TST.

How it works in practice

Interpreting a baseline result. The risk assessment helps interpret results. A worker with a positive test who has no symptoms, is unlikely to be infected and is at low risk of progression should get a second test (IGRA or TST), and should be considered infected only if both are positive.

After an exposure. A worker exposed to someone with potentially infectious TB without adequate protection should have a prompt symptom evaluation and, if they have no documented prior LTBI or TB disease, a test; if negative, it should be repeated 8 to 10 weeks after the last exposure, preferably with the same kind of test. Workers with documented prior infection do not need another infection test, but should be evaluated further if TB disease is a concern.

Targeted repeat testing. Facilities may still choose repeat screening for groups at higher occupational risk, such as pulmonologists and respiratory therapists, or in settings where transmission has occurred, such as emergency departments. Decisions should weigh how many patients with infectious TB are seen, delays in airborne isolation, and past evidence of transmission, ideally with advice from the health department. Because workers can also be exposed outside work or develop new risks, facilities should educate everyone annually about TB, encourage them to discuss possible exposures with their doctors, and base any later testing on each person's exposure risk since the last test.

After a positive result. A newly positive worker, confirmed where appropriate, should have a symptom evaluation and chest X-ray. Someone with a previous positive test and a documented normal X-ray needs another only if they have symptoms or are starting LTBI treatment. The health department should be told right away if TB disease is suspected. Workers with untreated LTBI should be offered, and strongly encouraged to complete, a recommended regimen, including short-course options; those who do not should have yearly symptom checks, be reevaluated for treatment, and be taught which symptoms need immediate attention.

Facilities are urged to work with public health agencies to find and treat LTBI among their staff and to share their experience, so the effect of the recommendations on U.S. TB rates can be judged.

Sources

• Sosa LE, Njie GJ, Lobato MN, et al. Tuberculosis Screening, Testing, and Treatment of U.S. Health Care Personnel: Recommendations from the National Tuberculosis Controllers Association and CDC, 2019. MMWR Morb Mortal Wkly Rep 68(19). https://www.cdc.gov/mmwr/volumes/68/wr/mm6819a3.htm
• Systematic review details: https://stacks.cdc.gov/view/cdc/77668