Physicians stress training in TB protection for HCWs

Two-step testing recommended for all new hires

Tuberculosis guidelines issued by occupational physicians emphasize the need to reduce health care workers’ risk of infection and to provide updated training for workers who are exposed to TB patients in hospitals and other health care settings.1

The American College of Occupational and Environmental Medicine (ACOEM) in Arlington Heights, IL, recently published recommendations based on the U.S. Centers for Disease Control and Prevention’s 1994 guidelines.2

In fact, ACOEM has produced a "short version" of the CDC guidelines, says lead author Lawrence W. Raymond, MD, ScM, director of occupational and environmental medicine at Carolinas Health Care System in Charlotte, NC, and a member of ACOEM’s Occupational and Environmental Lung Disorders Committee.

"We emphasize the need for training health care workers caring for TB patients. It serves as a reminder, because often in the heat of battle — in taking care of patients — we can forget we are potentially at risk and vulnerable, too," he says.

HCWs are at increased risk of acquiring "serious TB infections which may not respond to usual therapy" due to drug-resistant TB strains and a resurgence of active pulmonary tuberculosis, the guidelines state. Multiple steps suggested to reduce workers’ risk are:

• periodic training to maintain risk awareness;

• appropriate management of patients who might have undiagnosed TB in emergency, ambulatory, and inpatient settings;

• engineering controls, such as negative- pressure rooms, adequate air exchanges in rooms, stand-alone high-efficiency particulate air filter units, and ultraviolet germicidal irradiation when needed;

• masking patients with suspected TB when in uncontrolled areas of the facility;

• periodic tuberculin skin-testing of HCWs;

• mandatory respiratory protection of HCWs in contact with TB patients;

• periodic respirator fit-testing and training in proper care and use of respirators;

• updated written TB control plans.

In accordance with CDC guidelines, ACOEM supports the use of risk assessments individualized for clinical facilities and their components, the use of approved N-95 or powered air-purifying respirators for HCWs engaged in high-risk procedures such as bronchoscopy and sputum induction, and respirator fit-testing consistent with Occupational Safety and Health Administration guidelines. HIV-positive workers may need to be exempted from high-risk procedures, ACOEM states.

The organization also recommends that HCWs who are exposed to patients with active TB should be skin-tested every three to 12 months, "depending on the risk assessment. HCWs with unprotected close contact with a patient with active TB should be retested as soon as possible (new baseline’) and, if negative, again 12 weeks later."

Two-step testing advised

ACOEM also emphasizes the need for two-step testing of all newly hired HCWs who have not been tested within the previous 12 months.

"Any [hospital] seeing much TB should be testing all hires with the two-step method to avoid the appearance of a conversion that’s job-related, when in fact it’s just a booster phenomenon," Raymond says. "Sometimes by doing that, you can cut an apparent conversion rate from 3% to less than a tenth of that."

Raymond cites a recent study that was designed to identify more accurately hospital workers with TB infection at time of hire and to estimate conversion rates more accurately with annual retesting.

During a 46-month period, of 2,149 employees skin-tested, 642 had a positive test and 1,507 had a negative test, for an overall tuberculin positivity rate of 29.9%. Of the 642 employees, 563 (87.7%) had a positive skin-test result on the first tuberculin test, but another 79 had a positive reaction only on the second test, giving a false negative rate during the first test of nearly 5%. Another finding revealed that most employees (63%) who tested positive only during the second test were young (between 21 and 40 years old), contrary to popular belief.3

For true converters, ACOEM recommends six months of isoniazid (INH) therapy for HCWs 35 years of age or younger. Older people may be at higher risk of INH toxicity, "and it should be prescribed with added caution," the guidelines state.

Annual surveillance is advised for HCWs with a previously positive skin-test. Those workers should be questioned about symptoms of pulmonary TB, such as persistent cough, hemoptysis, night sweats, weight loss, and persistent fatigue.

HCWs with active pulmonary disease need immediate INH therapy, along with two or three other anti-tuberculosis medications. Those HCWs can return to work , "including patient care, after three consecutive daily sputum smears are negative for acid-fast organisms, providing they are responding clinically and radiographically to treatment," the guidelines state.

(Editor’s note: To access a copy of ACOEM’s TB guidelines on the World Wide Web, go to :http://www.acoem.org/paprguid/guides/tbguide.htm.)

References

1. Raymond LW and the American College of Occupational and Environmental Medicine Occupational and Environmental Lung Disorders Committee. Committee Report: ACOEM guidelines for protecting health care workers against tuberculosis. J Occ Env Med 1998; 40:765-767.

2. Centers for Disease Control and Prevention. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care facilities, 1994. MMWR 1994; 43 (No. RR-13):1-132.

3. Mohammadi M, Gupta K, Dhar SR, et al. Evaluation of two-step tuberculin testing in employees of a city hospital (Abstract). Chest 1998; 114:284S-285S.