TB draft guidance ducks fit-tests, urges IC

Frequency of worker testing linked to risk

The Centers for Disease Control and Prevention (CDC) has released new draft TB guidelines for health care settings that generally duck the controversial respirator fit-test issue but tie several infection control measures to facility risk assessments.

The Occupational Safety and Health Administration (OSHA) requires TB respirator fit-testing to be done annually. In acknowledging the requirement, the CDC guidelines stated, "Fit-testing should be performed during the initial respiratory protection training and periodically [emphasis added] thereafter. Perform fit-testing during the initial respiratory protection program training and periodically thereafter [based on the risk assessment for the setting], and in accordance with applicable regulations."

Regardless, OSHA currently is not enforcing the annual fit-test requirement. A provision in the huge federal appropriations bill that passed in late November prohibits OSHA spending federal funds to enforce the General Industry Respiratory Protection Standard annual fit-testing requirement as it applies to TB. It only applies to Fiscal Year 2005, which lasts until Oct. 1, 2005, and does not actually revoke the rule, which went into effect July 2.

The Association for Professionals in Infection Control and Epidemiology (APIC) and the American Hospital Association sought congressional relief from the annual fit-testing rule, which they contend places a great burden on hospitals but provides little benefit in employee protection.

An APIC spokeswoman said the moratorium on enforcement opens a window of time to pursue more long-term measures.

In updating its 1994 guidelines, the CDC noted that the epidemiology of TB has changed considerably. Those guidelines were issued in response to a resurgence of TB that occurred in the United States in the mid-1980s and early 1990s. The TB infection control measures recommended by the CDC in 1994 were implemented widely in health care facilities nationwide. The result has been a decrease in the number of TB outbreaks in health care settings reported to CDC and a reduction in health care– associated transmission of TB to patients and health care workers. In addition, public health TB control programs succeeded in reversing the upsurge in reported cases of TB disease, and case rates have declined in the subsequent 10 years.

However, the decline in case rate from 2002 to 2003 was the smallest decline since 1992, the CDC warned. In addition, despite the general decline in TB rates in recent years, a marked geographic variation in TB case rates persists, which means clinicians in different areas face different risks. Case rates vary from 0.9 per 100,000 population in North Dakota to 7.5 per 100,000 in New York and 9 per 100,000 in California.

Thus, TB should not be viewed with complacency, both for its historical ability to make a comeback and the fact that preparing for the agent is another step toward bioterrorism readiness.

"A new relevance to bioterrorism preparedness exists," the CDC stated. "Many of the activities and recommendations for the prevention and control of TB also will be useful for preventing transmission of agents of bioterrorism and diseases such as smallpox and SARS [severe acute respiratory syndrome]. Since agents of smallpox and SARS, for example, are transmitted by air, implementation of a comprehensive infection control program, including environmental control measures and a respiratory protection program, potentially will enhance health care settings’ preparedness for many agents that are transmitted by the airborne route."

The new Guidelines for Preventing the Transmission of TB in Health Care Settings, 2005, update and revise several recommended approaches to TB. Changes from the earlier guidelines include:

  • A risk-assessment process was developed that includes the assessment of more aspects of infection control.
  • The document uses the term "tuberculin skin test" (TST) instead of "PPD" (or purified protein derivative).
  • The whole-blood interferon gamma assay, QuantiFERON-TB (QFT) has been included as an option for detecting TB infection. QFT may be used in place of the TST in TB screening programs for HCWs.
  • The frequency of TB screening for workers has been decreased for many settings, and the criteria for determination of screening frequency have been changed.
  • The scope of settings to which the guidelines apply has been broadened to include laboratories and additional outpatient and nontraditional facility-based settings.
  • The document more clearly defines the health care workers who need to have serial tests of TB infection performed. In many settings, this change will decrease the number of workers who need serial TB screening.
  • In general, these recommendations apply to an entire health care setting rather than to areas within a setting.
  • The document uses the recently introduced terms "airborne infection isolation" (AII) and "airborne infection isolation room" (AII room).
  • Recommendations for annual respirator training and periodic respirator user seal checking (formerly called "fit-testing") have been revised.
  • The document recognizes the accumulating evidence that addresses respirator fit based on different manufacturers’ products.
  • Information on ultraviolet germicidal irradiation (UVGI) and room-air recirculation units has been expanded.
  • Additional information regarding multidrug-resistant TB and HIV infection has been included.

Conducting a TB risk assessment

Every type of health care setting should conduct initial and ongoing evaluations of the risk for transmission of TB of whether patients with suspected or confirmed TB disease will be encountered in the setting, the CDC draft recommends. The TB risk assessment determines the types of administrative and environmental controls and respiratory protection program needed for a setting and serves as a tool for the ongoing evaluation of the quality of TB infection control and the need for improved infection control measures. A TB risk assessment for the setting should be conducted and documented at least annually.

The TB risk assessment determines the risk for health care-associated transmission of TB in the setting by examining a numbers of factors:

1. community rate of TB disease;

2. number of patients with TB disease presenting for care in the setting, regardless of whether they stay in the setting or are transferred to another health care setting;

3. timeliness of the recognition, isolation, and evaluation of patients with suspected or confirmed TB disease;

4. evidence for transmission of TB in the setting;

5. the types and conditions of the environmental controls present in the facility.

The guidelines include risk-assessment worksheets that can be used as a guide. The findings from the risk assessment will form the basis for decisions about the level of administrative, environmental, and respiratory protective measures needed to ensure a safe environment for HCWs, patients, and others. For example, frequency of TB screening of health care workers varies according to whether the risk of transmission is low, medium, or high, as follows:

Low risk

  • All workers should receive baseline TB screening upon hire using baseline two-step TSTs or QFT to test for infection with TB.
  • Workers with a baseline positive or newly positive TST result should receive one chest radiograph to exclude a diagnosis of TB disease. After this baseline chest radiograph is performed and the result is documented, repeat radiographs are not needed unless signs or symptoms of TB disease develop, a clinician recommends a repeat chest radiograph, or one is required as part of a contact investigation. Instead of participating in serial skin testing, the HCW should receive a medical evaluation and a symptom screen. Offer treatment for latent TB infection (LTBI) to those who are eligible. After baseline testing for infection with TB, workers in settings classified as low risk do not need further TB screening unless an exposure to TB occurs.

Medium risk

  • All workers should receive baseline TB screening upon hire using two-step TSTs or QFT to test for infection.
  • Workers with a baseline positive or newly positive TST result should receive one chest radiograph to exclude a diagnosis of TB disease. After this baseline chest radiograph is performed and the result is documented, repeat radiographs are not needed unless signs or symptoms of TB disease develop, or a clinician recommends a repeat chest radiograph, or as part of a contact investigation. Instead of participating in serial skin testing, workers with positive TST or QFT results should receive a symptom screen and a medical evaluation. Offer treatment for LTBI to those who are eligible.
  • After baseline testing for infection with TB, workers in settings classified as medium risk should receive TB screening annually (i.e., symptom screen and testing for infection).

High risk: Potential for ongoing transmission

Testing for infection with TB may need to be performed every eight to 10 weeks until lapses in infection control have been corrected and no further evidence of ongoing transmission is apparent.

[Editor’s note: The draft TB guidelines can be viewed at http://www.cdc.gov/nchstp/tb/. Submit e-mail comments to TBInfectionControl@cdc.gov. Please include the specific section, subsection, and page number for each comment. You also may submit comments by fax (404) 929-2676) or by mail to: Centers for Disease Control and Prevention, Division of TB Elimination, 1600 Clifton Road, N.E., MS E-10, ATTN: Lauren Lambert, Atlanta, GA 30333.]