Broader exemptions expected for annual tests
New TB infection control guidelines proposed for health care facilities are expected to free many low-incidence facilities and parts of the country from the burden of having to do annual purified protein derivative (PPD)-tuberculin testing on employees, federal TB experts say.
The scope of the change promises to be extensive, given that in the year 2000, 22 states (44%) fell into the low-incidence category, and 1,606 individual counties reported no TB cases. As in the old guidelines, facilities still will be required to give PPD tests at baseline and upon exposure.
With a bit of luck, the new guidelines should be out by the end of the year, says Renee Ridzon, MD, a medical epidemiologist at the National Center for Infectious Disease at the Centers for Disease Control and Prevention (CDC) in Atlanta.
The change reflects a growing consensus among experts that annual PPD testing in a low-incidence setting produces too many false-positive results and consumes too many resources to justify continuing. "The rate of false-positives in general, false-positives from nontuberculous mycobacteria, and the fact that annual testing is a resource-intensive activity when done in low-incidence areas — all of that went into our thinking," Ridzon says, explaining the rationale for the change in the guidelines.
OSHA plans to make similar changes
Even at the U.S. Occupational Safety and Health Administration (OSHA), an agency not known for pushing fewer regulations, there is the sense that doing annual PPD testing has ceased to be useful in some settings. "The CDC has told us there’s a problem of overtesting certain groups, and I think most people now buy off on the concept that annual PPD testing in certain areas is not as useful as you might think," says Amanda Edens, MPH, an OSHA industrial hygienist closely associated with the agency’s proposed TB rule. OSHA will very likely modify its compliance directive, as well as its proposed rule, to reflect the change in the CDC’s guidelines as soon as they are published, Edens adds. "We’ve always tried to mirror their guidelines on that subject," she says. "Plus, it would be terribly confusing to people if we didn’t, because people wouldn’t know which standards to go by."
The new CDC guidelines appear headed for publication in the Federal Register. Comments gathered from that then must be considered before the rule can take effect. The year-end publication date is just a best guess, Ridzon emphasizes. Plus, because the document is still in draft form, theoretically changes still could occur in the new risk category formulation.
Streamlining risk categories
The guidelines are expected to take the four risk categories elucidated by the 1994 guidelines1 and streamline them down to just three — low, medium, and a high-risk category that signifies ongoing transmission (and so doesn’t actually qualify as a category, since it’s hopefully only a transient condition, Ridzon points out). All facilities that qualify as low risk will be exempted from annual PPD testing, though they’ll still be obliged to test at baseline and upon exposure.
Whether a facility meets the low-risk definition depends on its size. Fewer than six cases per year qualifies as low-risk in facilities of 200 beds or more; fewer than three equals low-risk for places with less than 200 beds. TB clinics, of course, will still be required to test on an annual basis, since by definition they treat active TB cases. The small proportion of TB clinics that treat only people with latent infection also may be exempted from having to test every year, Ridzon says.
In low-incidence areas where two-step testing at baseline doesn’t produce enough cases to justify the practice, two-step testing also will be waived, though that’s not really a change. The 1994 document already allows for skipping two-step testing under such circumstances, Ridzon points out. "It was a bit cryptic on that point, though, so not everyone may have realized that," she adds. The new document will have a section on frequently asked questions intended to clarify subjects that provoke the most questions.
Freeing up resources to do other work
Infection control professionals say the change will come as welcome relief. "For our facility, this will offer a great time savings," says Virginia Bren, RN, CIC, infection control coordinator of Altru Hospital in Grand Forks, ND. "Of course, we’ll still have to do the risk assessment and the education and all the rest; but that one corner will be gone, and we’re looking forward to that."
TB controllers in low-incidence states agree the change is a step in the right direction. "Our sense is that we do way too much skin testing in North Dakota currently," says Karin Mongeon, manager for North Dakota’s state TB program.
"I’m very glad they’re refining these recommendations," echoes Christine Hahn, MD, TB control officer of Idaho. "Routine skin testing really drains our energies away from more important activities, such as contact tracing."
The new guidelines are also expected to provide new or additional recommendations on environmental controls, air cleaning technology, pressure differentials in airborne infection isolation rooms, and ultraviolet germicidal radiation. Many of these new directives will reflect more closely recommendations already promulgated by the American Institute of Architects, Ridzon says.
Paul Jensen, PhD, chief of the laboratory research branch at the Division of Respiratory Disease Studies at the National Institute for Occupational Safety and Health (NIOSH), declined to elaborate on those changes, saying he would make comments once the guidelines are published.
Reference
1. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health care facilities, 1994; MMWR; 1994:43:10.
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