College of American Pathologists
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  Taking stock of biosafety perils in surg path


CAP Today




September 2009
Feature Story

Anne Ford

The medical technologist who contracted brucellosis on the job. The pathologist who became TST-positive after being accidentally exposed to a specimen from a tubercular patient. The laboratory that never turned on its biosafety cabinet because it made too much noise. For personnel who work in the microbiology laboratory, telling horror stories like these is the equivalent of screaming, “The call is coming from inside the house!”

“You hear about people who become ill after being exposed to infectious organisms in the microbiology lab and die from it,” says Nancy Cornish, MD, director of microbiology at Methodist and Children’s hospitals, Omaha, Neb. “A couple of stories like that, and you realize how easy it is.” Fortunately, in the age of multidrug-resistant TB, anthrax, SARS, West Nile virus, and now H1N1, biosafety precautions have largely become second nature in the microbiology laboratory. But like all classic horror stories, this one has a sequel. Call it “Nightmare on Surg Path Street.”

That is, the biosafety precautions so strictly adhered to by microbiology personnel are generally not nearly as high on the radar of their colleagues in surgical pathology, say Dr. Cornish and other experts. “We have focused on microbiology because that’s where the bugs are,” Dr. Cornish says. “But we have not paid attention so much to anatomic pathology.”

The discrepancy is particularly alarming given that surgical pathology laboratories present many of the same biohazards as microbiology labs. “‘Wait a second,’” Dr. Cornish, who trained in both microbiology and surgical pathology, remembers thinking in her early days of practice. “What I’m doing in surg path is really no different than what I’m doing in microbiology, so why are the rules different? Why are people in surgical pathology not following the rules that we follow in micro?”

As in microbiology, biosafety hazards in the surgical pathology laboratory aren’t just Hollywood bogymen. If anecdotal reports are to be trusted, just about every lab, it seems, has had at least one instance of a staff member being accidentally exposed to dangerous pathogens. As for hard data on the phenomenon, little exist. Of course, that’s part of the problem.

Another part of the problem: Surgical pathologists and their staffs have no official means of learning from each other’s experiences in this area. “If we’re all little islands, and it [a biosafety accident] happens to us but we don’t tell anybody about it, or it happens to someone else and they don’t tell anybody, then nobody can get together and say, ‘Hey, we have to change our process,’” Dr. Cornish points out. “I suspect that it’s happened a lot more than people realize; it’s just not been documented.”

She urges surgical pathology laboratories to begin raising questions about their own biosafety practices, such as: Do we require annual TSTs for pathologists? Do we require personnel who cut frozen sections to wear masks, and if so, under what circumstances? Who is responsible for investigating exposures after the fact? By doing so, those in the surgical pathology suite can begin to raise their level of biosafety awareness and perhaps protect their health and that of their colleagues. As Dr. Cornish urged her audience in “Biosafety Beyond the Walls of the Microbiology Laboratory,” a talk at the American Society for Microbiology general meeting in Philadelphia, earlier this year: “Ask these questions. Someone’s life may depend on it.”

The lesser emphasis on biosafety in many surgical pathology laboratories is likely to stem in part from the nature of the work conducted there. Michael A. Pentella, PhD, D(ABMM), saw that firsthand during his years as manager of a clinical laboratory. “I think that the surgical pathology area presents real challenges,” he says. “You need to handle things very quickly and extremely accurately. You have to contain them appropriately, yet work with them with a fair amount of speed.” Dr. Pentella is now associate director of the University of Iowa Hygienic Laboratory and associate clinical professor in the University of Iowa College of Public Health’s Department of Epidemiology.

For one thing, as Dr. Cornish said in her ASM talk, “You want to get results ASAP so the patient doesn’t spend additional time under anesthesia, which is not a benign procedure.” It’s easy to see how biosafety might end up shunted aside in that kind of fast-paced environment.

Then, too, physicians often neglect to let the laboratory know when a potentially biohazardous specimen is on its way. “Clinicians are notorious for leaving infor­mation off the requisition,” says Pamela Gibson, MD, associate professor of pathology, University of Vermont College of Medicine, and director of surgical pathology quality assurances and compliance, Fletcher Allen Health Care, Burlington. “It’s just amazing what someone forgets to tell us in the way of important information. I think a lot of people put reliance on somebody else telling the lab, or they think that because they know it must be widely known, or it must be in the record, so that everyone who interacts with the patient’s going to know. But it’s not obvious.”

“It just doesn’t occur to them,” Dr. Cornish agrees. “I’ve said this to a couple of our surgeons: ‘You need to tell us if you think it’s going to be TB, because we cut these on the cryostat, and we could get exposed to TB.’ And they’re like, ‘Really?’ When you’re down in the OR, you’re wearing a mask, and you’re completely covered. It’s not something people [in there] talk about or think about, really. I guess it’s a matter of walking a mile in somebody else’s shoes.”

Part of the reason the laboratory is often not warned in cases like these is that many clinicians simply haven’t been trained in biosafety. “Biosafety in the laboratory is something that’s really covered more during a rotation of microbiology,” Dr. Pentella says. “In medical school, it’s certainly not covered.”

Even in training, “we were taught how to gown up and glove and that kind of thing, but I don’t think I was really ever taught why I was doing all that,” Dr. Cornish says. “Basically, the attitude was: ‘You don’t want to mess up your street clothes.’” In one extreme example, as she recalled in her talk at ASM, one of her pathology instructors didn’t even wear gloves when examining specimens: “He said to me, when I would talk to him about it, ‘I’ve never worn gloves. I’ve never gotten sick. I’m not about to start now.’”

Along similar lines, she had another pathologist tell her that because he was already TST-positive, he didn’t need to take precautions against tuber­culosis exposure. “What about everyone else in the room?” she asks. “What’s to stop him from becoming infected with a different strain of TB?”

In addition, surgical pathology personnel may underestimate biosafety threats in their environment because they may be unconsciously assuming that a fixed specimen is a safe specimen. “So you think, ‘Oh, there’s no problem,’” Dr. Cornish says. “Well, if you don’t fix it with the right ratio of formalin to tissue, or you cut it fresh—which we do sometimes—or you’re doing a frozen section where the tissue is fresh, those rules are off.”

Kimberle Chapin, MD, director of microbiology for Lifespan Academic Medical Centers, Providence, RI, even questions whether tuberculosis is really killed in formalin-fixed tissues: “You assume that it is, but I look in the literature and see that maybe that isn’t the case all the time. I found something from around 1920 that said it varies depending on length of contact, existing temperatures, and how much tissue you’re fixing. And I just found a case in 2004 that talked about 138 autopsy cases with histology-proven TB and the viability of the tissue. So it has to be regarded as potentially infectious.”

Another potential unconscious assumption: that specimens from live patients present fewer biohazards than specimens taken during autopsy. “We’re in general more careful when we do autopsies,” Dr. Cornish says. “You’re cutting fresh tissue that could have an infectious disease in it—I think we’re more aware of that in the autopsy suite.” Not that there aren’t plenty of anecdotal reports of accidental exposures during autopsies, but gen­erally speaking, biosafety practices during autopsy appear to be better established. Ironically, that may lead to a false sense of safety outside the autopsy suite. The temptation may be to assume, “If we’re not following the same practices in the surg path suite that we follow in autopsy, the potential danger must not be as great.”

One practice that, by all accounts, is often inconsistently implemented: the wearing of N95 masks during frozen sectioning. CLSI guidelines (“Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline—Third Edition,” 2005) flatly state, “Gloves and an N-95 particulate respirator should be worn during frozen sectioning.” But even laboratories that strictly adhere to this guideline may be inadvertently exposing their workers to pathogens by not performing annual fit-testing. “The issue for most places is actually taking the time to make sure people are fitted properly,” Dr. Chapin says. “I think there are a lot of people who might say, ‘I don’t want to be bothered,’ and unless they are mandated to be properly fitted, they may not be.”

Her own institution, Lifespan, performs fit-testing every year, she adds. But fit-testing protects only the people actually wearing the masks. “When we’re cutting in the frozen section room, if we have a TB case and we don’t know that up front, the operator is wearing an N95 mask, but everyone else in the room may or may not be,” she says. And there’s always the temptation to cut corners by skipping the N95 entirely when TB is not suspected. “N95s aren’t all that comfortable,” Dr. Cornish says. “It can be hard to breathe all the time through it. But of course it’s not comfortable to get TB, either.”

On the flip side, others worry that the cumbersome nature of N95s might pose its own safety hazards. In her own talk at ASM, “Establishing a Biosafety Culture,” Kathleen Beavis, MD, chair of microbiology and virology, John H. Stroger Jr. Hospital, Chicago, said: “I think we also have to realize—those of us who have worn N95s for hours at a time—there’s a cost to doing that as well in terms of comfort, being able to breathe. And I worry that these additional burdens can cause their own safety challenges.” That’s why more hard data on the benefits of N95s and other biosafety measures are needed.

All the biosafety awareness in the world goes only so far if surgical pathology laboratories themselves are not set up in a way that maximizes protection from pathogens. And Dr. Cornish doubts many of them are. In her ASM talk, she noted, “We need to make it easy to do the right thing” by putting as many biosafety features on auto-pilot as possible—for example, by instituting automatic yearly reminders of the need to be fit-tested for N95 masks.

Then again, some of the biosafety features she’d like to see implemented don’t appear to exist. One such feature: biosafety hoods for the surgical pathology laboratory. “I never had one when I was cutting, and we don’t have one in our autopsy suite or in our surgi­cal pathology suite,” she says. “When we were looking for hoods to use in our surgical pathology suite, I wanted to find one that was a biosafety hood, and I couldn’t find one. They sell all kinds of fancy cutting stations, but basically they’re designed to keep formalin away from the person who’s cutting, not organisms.”

Even if a hood like the one Dr. Cornish seeks were readily available, many labs might not have the space for it. “The problem is where we would put that,” Dr. Gibson says. “I think at most places, space gets cut quickly as you’re designing something.” That’s assuming you’d even have the luxury of designing from scratch, rather than trying to retrofit existing space. Still, Dr. Gibson says, “I would think that would be better for your employees to have that [a hood].”

An even more desirable biosafety feature, at least in Dr. Cornish’s eyes, would be a cryostat with negative air flow, which—like the surgical pathology biosafety hood—has so far proved as elusive as the unicorn. “The cryostat that we use does not have any kind of negative air flow,” she says. “It doesn’t have any downdraft. You’re cutting sections that are basically flash-frozen. You’re cutting them very thin. You get all kinds of tissues, as you cut, aerosolizing upward into your face. I talked to the cryostat companies, and they said, ‘Oh, that’s a good idea’”—that is, creating an instrument with negative air flow—“but no one’s actually designed a cryostat that would do that.” Perhaps most frustrating of all, she says that when she told this to pathologists, their response was: “Well, if they don’t make them, it must not be important.”

Au contraire, says Dr. Chapin, who agrees that cryostats pose an aerosolizing hazard. “Often the top of the instrument is open, and you’re creating aerosols,” she says. “That’s clearly the most obvious place where infection could occur. Most of these things [exposures to infectious agents] are identified after the fact. They go back and clean the instrument, but at that point, everybody in the room has already been exposed.”

“Our group is doing extremely well [at reducing biosafety hazards],” Dr. Chapin continues. “But they are still at risk because they don’t have a cryostat that is fumigated the correct way.” She’d like to see “companies come up with a fix for those kinds of instruments so they [her staff members] don’t even have to wear an N95 mask.” “There are some cryostats that have the ability to remove fumes,” she adds, “but they do not have the ability to remove infectious agents. Obviously that would be the optimal thing, if you could make that cryostat with a filter on it so that all those agents that might get aerosolized could be eliminated as a danger. Could you potentially attach something to the cryostat instrument creating air flow through filters?”

Drs. Chapin and Cornish raise another cryostat biosafety issue: the widespread but unwise use of propellant in a can to flash-freeze tissue. Says Dr. Chapin: “Right now, the way a cryostat works is that if you put a piece of tissue on the area where it will freeze to -20°C, it takes about 15 to 20 seconds for it to freeze. Some people don’t like to wait, so they’ll use a spray that will freeze it more quickly. The pathologist’s concern is: We’ve got to freeze it fast. The surgeon is trying to make a diagnosis while the patient is on the table under anesthesia. Fortunately, the sprays are not used here anymore at Lifespan.”

Why not? Dr. Cornish explains the danger: “I can’t tell you how many times I’ve seen people spray right into the cryostat. Then what happens is, you aerosolize all those fragments of tissue that are sitting in the bottom of the cryostat—because after you’ve cut frozens all day, you have 10 or 12 patients’ tissues in the bottom just sitting there—back into your face.”

Leica Microsystems marketing manager Jan Minshew, HT/HTL(ASCP), is particularly opposed to freezing spray. “There is a definite problem in the way it is used,” she says. “Users are aerosolizing all of those pathogens in the cryostat, and it goes right into their breathing zone. There are other means of doing quick freezing, and I don’t think spraying is the best possibility.” One alternative method, she notes, entails orienting and freezing the specimen on a cold metal bar, then adding freezing medium and the chuck.

In addition, many newer cryostats, such as Leica’s CM1850 and CM1950 series, feature built-in Peltier units that can cool specimens rapidly enough for routine work. “Our competition has the same thing,” Minshew says. “Everybody has provided a means for freezing faster. It’s just that people are used to using those sprays, and they do it without thinking about what’s happening.”

Another cryostat-related biosafety concern to which laboratories should devote more thought, in Minshew’s view, is decontamination. “Many people don’t understand what substances can be used,” she says. “The CAP guide­line requires that, if a cryostat is used daily, it must be disinfected with a tuberculocidal disinfectant each week, and there’s a lot of misconception about what can be used and at what temperature. The majority of EPA-approved tuberculocidal disinfectants must be used at room temperature, but people don’t always understand that.” Minshew adds: “A lot of people will use absolute alcohol, and that is not as effective as a dilution of 60 to 90 percent because the presence of water causes proteins to denature more quickly. Seventy percent ethyl or isopropyl alcohol has enough water to get in and do the job, and it works just fine in a cryostat. It can always be followed by absolute ethanol, but that’s not usually necessary.”

A final note on cryostats: They should be in a separate area whenever possible, Dr. Cornish says, to avoid stirring up random air flows as people walk by. In addition to being in a separate area, it would be ideal to have that area blocked off by a door that could be closed in case of a contamination event, but that would contain glass so laboratory personnel could see in and out.

“To be honest, there’s a big void of knowledge about how much [biosafety] protection we really need,” Dr. Chapin says. Hence “there really are not a lot of clear guidelines specifically for surgical path like there are for microbiology right now.” That’s something she’s hoping to help begin remedying as she assists the Centers for Disease Control and Prevention in creating a new document on biosafety in clinical laboratories, which is expected to be available early next year.

That document stems from a Blue Ribbon Panel for Issues of Clinical Laboratory Safety, which the CDC convened in May 2008, and on which Drs. Pentella and Beavis served. The executive summary that emerged from that panel notes, among other things, “Neither the number nor the causes of LAIs [laboratory-acquired infections] in clinical laboratories is fully known,” “the ability to determine and monitor the frequency of such occurrences is desirable,” and that while “many professional, accrediting, training, and standards development organizations are already making efforts to address the safety of laboratory workers,” “the panel felt that more work is still needed.”

The guidelines in development, Dr. Chapin says, will not be so much a comprehensive, step-by-step biosafety bible as an outline of the minimal biosafety requirements and precautions in the laboratory—receipt of specimens, safety regarding stains and chemicals, proper disposal, and personal protection. “There needs to be a start to make things more consistent,” she says. “At least we can get on the same page about what we should be doing, and then maybe we can start specifically addressing what the risks are.” One of those risky practices that will, she says, “absolutely” be labeled inappropriate under the new guidelines: spray freezing of specimens at cryostats.

At the same time, Dr. Pentella says, the CDC and Association of Public Health Laboratories are working toward developing core competencies for BSL 2, 3, and 4 laboratories. “Since the surgical path suite would be considered a BSL 2 lab, that would apply to this,” he notes. “That will be very helpful to the training of individuals who work in these labs. For example, students. What training should they be given ahead of time? Right now it’s left up to the individual lab, possibly the individual instructor. With more guidelines, we can have some standardization of practices.”

Also under development is a new edition of the CLSI’s “Protection of Laboratory Workers from Occupationally Acquired Infections,” last issued in 2005. Those guidelines currently advise against the use of spray freezing agents and recommend, among other measures, that surgical pathology personnel use N95 masks during frozen sectioning, decontaminate cryostats “frequently” with 70 percent alcohol, and use biosafety cabinets when “the risk of substantial spatter or aerosolization is present.” Dr. Cornish hopes the new edition will add a recommendation that cryostats be in a separate area.

She also hopes that surgical pathologists will become more aware of the CLSI guidelines’ existence. “I’m not sure everybody knows about them,” she says. “I know about them because I’m doing clinical microbiology, so I went in as a clinical microbiologist to review them to make sure we’re doing what we need to do. I don’t know that anatomic pathologists would know that there’s guidelines in there for them as well.” (It doesn’t help, she noted in her ASM talk, that the guidelines are listed under “M” for “microbiology” in the CLSI’s indexing system, so “how many anatomic pathology staff are going to see them?”) However, she notes, some of the younger pathologists she’s encountered were trained to wear N95 masks when doing frozen sectioning, “so some residency programs seem like they’re teaching” with the CLSI guidelines in mind.

As for the CAP Laboratory Accreditation Program, currently two questions pertain specifically to biosafety in surgical pathology. GEN.71220 asks, “Does the laboratory have a documented tuberculosis exposure control plan?” while ANP.12087 asks, “Is there a documented procedure for the routine decontamination of the cryostat at defined intervals, and are decontamination records evident?” These questions don’t go far enough, Dr. Cornish implied in her ASM talk: “CAP checklists for anatomic pathology do not specifically cover biosafety issues. CAP checklists for general lab safety are just that—general. If you have not been taught principles of bacteria/viral spread or biosafety issues, these questions will not educate you so that you can change or improve your environment. The questions are well referenced; in the middle of an inspection, are you going to read references?”

If you’re just beginning a surgical pathology biosafety initiative, it’s probably best (and easiest) to start with the basics already mentioned: Make sure everyone wears fit-tested N95 masks during frozen sectioning. Reduce cryostat-produced aero­sols by outlawing freezing spray. Try to find room for your cryostat in a separate area, and use a tuberculocidal disinfectant in the routine defrosting and decontamination of the instrument.

Dr. Gibson, however, has another tip that can help head biosafety hazards off at the pass. “Our pathology assistants have gotten more and more access to the electronic health record,” she says. How does this help? Because “they can, at the beginning of the day, look up every potential case coming down for a frozen section and pin up clinic notes, x-rays, all sorts of stuff, so when that specimen comes down, we have a heads-up on things that the clinicians aren’t going to tell us about. You just don’t get that otherwise with the small amount of space on a requisition. That’s been the best thing we’ve done to be proactive.”

One final point: Safety, bio- and otherwise, is a laboratorywide issue, and it’s vital to create a workplace culture that emphasizes that. As Dr. Beavis put it in her ASM talk, “We can have the best procedures and all the personal protective equipment in the world, but if the technologists are not buying into this, it’s going to be a failure.” To that end, she brought a camera into her laboratory one day and told her technologists to anonymously take photos of things in the laboratory that seemed unsafe. She then posted the pictures, and as each item was remedied, put an X through the appropriate photo. “This was so helpful, because many of these things were things I had stopped seeing, or that bugged one person while it didn’t bug other people,” she said. “It was a way to show the technologists that we valued their input. We really need to foster an atmosphere in the laboratory that we’re all responsible for it, and we all benefit from this.”

Anne Ford is a writer in Chicago.