CDC may revise skin test and respirator rules

Federal reg in limbo, IOM report due soon

The Centers for Disease Control and Preven-tion will likely scale down recommendations for worker skin testing and tackle the controversial issue of respiratory protection in revised guidelines for preventing tuberculosis transmission in health care settings, Hospital Infection Control has learned.

The proposed CDC revisions, which are still in the early stages, were recently outlined in Atlanta at a meeting of the CDC Healthcare Infection Control Practices Advisory Committee (HICPAC). The move further complicates the TB picture, raising questions about the long-delayed federal standard because it primarily was based on the 1994 CDC guidelines that now are being revised.

The Occupational Safety and Health Admini-stration (OSHA) has lost considerable momentum in finalizing its 1997 proposed standard, setting it aside in 2000 to focus on passage of its ergonomics standard. Plans now call for the OSHA standard to be finalized sometime in 2001, but that effort could be undercut further by an impending report by the Institute of Medicine (IOM) in Washington, DC. The IOM, which held hearings last August to review the need for the OSHA TB standard, is expected to issue its recommendations on the matter early in 2001.

"To me, the best outcome would be for OSHA to totally abandon its requirements and to return to the days when CDC guidelines, which always have some flexibility in them, are the best practice," HICPAC member William Scheckler, MD, told HIC.

The CDC changes under discussion include less frequent skin testing of health care workers, particularly in low TB prevalence areas where positive tests are likely to be false, Adelisa Panlilio, MD, medical epidemiologist in the CDC Division of Healthcare Quality Promotion, told the HICPAC panel. "Some areas of the country that have a very low prevalence of TB, such as Montana and New Hampshire, are testing all health care workers annually," she said. "Whenever they find a positive [test] they don’t believe it and [keep] testing to try to make the positive go away."

What is the frequency?

The CDC advised annual testing in its 1994 guidelines for "low-risk" settings, but will now likely revise that recommendation. The specific recommendation has not been determined, but some argue that testing on hire for baseline data is probably sufficient.

"I think that is probably not even necessary, although depending upon where our workers come from, it is probably still prudent," said Scheckler, hospital epidemiologist at St. Mary’s Hospital in Madison, WI. "But annual testing is simply unnecessary in our setting."

Annual TB testing of workers was historically done at his hospital, but the practice was dropped because no evidence of transmission was found in a review of the data from 1970 to 1980, he told HIC. "We looked at all of the patients we had in that 10 years that had TB, both pulmonary and extrapulmonary, and we looked at all of the employees who had any evidence of conversion in that 10 years."

"We found there was absolutely no contact between those employees and the very few patients that we had [with TB]," he said. How-ever, the testing policy was subsequently reinstated after OSHA proposed its standard and began enforcing TB provisions under its general duty clause pending finalization of the rule.

"Right now, we are required to test our candy stripers’ — our volunteer high school students — who are only in the hospital for a couple of months," Scheckler said. "But OSHA says, thou shalt test them."

Indeed, with TB in national decline, experts have warned that frequent testing of workers in low-prevalence areas will yield false-positives and possibly inappropriate treatment. John Bass, MD, chairman of the department of internal medicine at the University of Alabama at Birmingham, estimates that the false-positive rate is at least 1% of the workers tested.

So for example, a hospital that skin tests 1,000 employees a year and has seven positives has a conversion rate of 0.7%. According to Bass — who testified at the IOM hearings — those seven conversions will almost invariably be false positives because they fall below the 1% benchmark. (See TB Monitor, October 2000, under archives at HIConline.com.)

Additional areas for CDC revision include extending the TB guidelines to nonhospital settings, updating laboratory guidance, and revisiting engineering controls and respirator recommendations, Panlilio said.

A problem that surfaced in HICPAC discussions is that N95 masks certified for use against TB are difficult to fit-test, a common component in industrial respirator programs that involves testing the seal of the mask around the worker’s face. That requirement is particularly concerning if OSHA codifies its standard, she adds.

"I hope we will get rid of the fit-testing requirement for the N95 respirator," Scheckler told HIC. "We [should] use a good mask that fits reasonably well, but not require fit-testing, HEPA filter masks, or these other space-suit things. Epidemiologically, they have not proven to be useful at all."

Such concerns are not going unheard, according to Michael Tapper, MD, a member of both the HICPAC committee and the IOM panel that is reviewing the OSHA TB standard.

"With respect to the issue of fit-testing and respiratory protection programs, I think it would be fair to say the [IOM] committee was very aware of the controversy surrounding this issue and had very intense discussions," Tapper told HICPAC members.

He declined to further characterize the IOM discussions prior to release of the panel report.