July 2009
Feature Story

Anne Ford

To any microbiology directors who may be tempted to assume their work begins and ends at the doors of the laboratory, Nancy E. Cornish, MD, and Carol A. Rauch, MD, PhD, have a message: When it comes to specimen collection, you’re responsible not just for managing the samples that come your way, but at least in part for managing the expectations and practices of the people who send you those samples as well.

“Whether you like it or not, we in the laboratory are responsible for educating our physicians on when to collect a specimen and how to collect it,” Dr. Cornish told attendees of “How and Why to Get the Right Specimens for Microbiology and What to Do When You Don’t,” a talk she co-presented with Dr. Rauch May 20 at the general meeting of the American Society for Microbiology in Philadelphia. “I know that feels difficult because you’re not up there on the floor, but we have to figure out a way to do it, and do it effectively.”

Dr. Rauch agreed. “Preanalytical variables have a tremendous impact on what results we generate,” she said. “So many parts have to go well.” In the past, it was easier to simply request another specimen if the first one was unacceptable, she pointed out. “Most of your patients were down the hall. They were a captive audience.” Now that so many more patients are outpatients, it’s more crucial than ever to obtain a quality sample the first time.

Dr. Cornish is director of microbiology at The Pathology Center and Children’s Hospital, Omaha, Neb., while Dr. Rauch is chief of the Division of Clinical Pathology and director of clinical microbiology at Baystate Medical Center, Springfield, Mass.

In their talk, Drs. Cornish and Rauch offered several tips for getting clinicians on board with best microbiology specimen collection practices, as well as a few refreshers on what those best practices entail. Dr. Cornish began by discussing a study that found that between five and 50 percent of all inpatient lab test orders are inappropriate (van Walraven C, Naylor C. JAMA. 1998;280:550–558). That number includes cultures, she said, including those performed from surgical specimens.

One reason that many inappropriate surgical specimens are sent for culture, Dr. Cornish said, is a widespread lack of recognition that not all wounds are infected. In her experience, some residents “will culture anything that is open”—decubitus ulcers, diabetic foot ulcers, poorly healing surgical wounds, recent traumatic wounds —regardless of whether those sites exhibit clinical signs of infection, such as the presence of pus. “Any time you have an open, wet surface, it is going to be colonized with bacteria,” she said, but that doesn’t mean infection is present. “We can culture that gooey spot on somebody’s leg, but we know we’re going to grow something, so there’s no point in doing that” if the site isn’t infected.

Then, of course, there are the countless times that microbiology laboratories receive a swab of the specimen, rather than the specimen itself. “They do a drainage of the abscess and stick a swab into the empty cavity and send us the swab and throw out everything else,” Dr. Cornish said. “Don’t give us one cc and throw out the rest.” She is a fan of the guideline that the same specimen be sent to microbiology as would be sent to surgical pathology.

A cautionary tale from Dr. Cornish’s institution reveals the dangers of improper specimen collection. A 55-year-old woman presented with an ulcerating breast infection. Pus appeared to be present, but other signs of infection were absent. A swab specimen taken for culture grew P. aeruginosa, E. coli, and coagulase-negative Staphylococcus. Three ineffectual courses of antibiotics later, the medical technologists called Dr. Cornish, who contacted the clinician and recommended tissue biopsy for histology and culture on the suspicion that what had been thought to be pus could actually be necrotic tumor. She was right. The patient had infiltrating ductal carcinoma, with only superficial colonization of the ulcerated area by bacteria and fungus—and her cancer diagnosis had been delayed for four weeks. That delay could have been avoided if tissue had been sent for histology and Gram stain and culture originally. “That’s why I preach that we’ve got to get the right specimens right up front. A swab for culture will not diagnose a tumor, unless you’re real good at looking at those Gram stains,” Dr. Cornish told the audience.

In getting points like these across to clinicians, it helps to strategize. Otherwise, Dr. Rauch said, “these dialogues can be confrontational.” One thing to remember, Dr. Cornish added, is that “even the clinician who’s arguing with you about something they know nothing about has the same goal in mind—patient safety. You just have to understand where each other is coming from.” Dr. Rauch agreed, saying, “I think a real trick to getting onto the same playing field is to start by saying, ‘Tell me about your patient.’ Don’t ever start with policy and compliance. It all sounds like red tape.”

Not surprising, Dr. Cornish continued, “if you use the right words, you get better cooperation.” That’s why she avoids telling a clinician that a specimen has been “rejected,” preferring to say “I’m unable to test it.” It also helps to keep your sense of humor: “If you can get people laughing, they’re more likely to listen to you.” To that end, she offered some “fun facts” about normal human flora that the average clinician likely doesn’t know, such as that in the average human, the bacterial component weighs about 1.25 kilograms, and bacterial cells outnumber mammalian cells by a factor of 10. (These facts can not only improve your working relationships but also prove to be great icebreakers at parties, she added.)

In addition to cultivating individual relationships with clinicians, Dr. Cornish stressed, it’s important to build teamwork between surgical pathology and microbiology lab personnel. “We need to build that relationship for improving patient safety,” she said. Good teamwork can prevent misdiagnoses, catch overlooked orders, and highlight additional relevant tests. To facilitate that teamwork, her institution has begun to include microbiology culture requests on surgical pathology requisitions. “Now, I can’t lie to you—a lot of times, the form is not filled out completely,” she said. “We are working with nursing on that, and we will get there.”

Another effort that has improved the quality of the microbiology specimens Dr. Cornish’s laboratory receives is a poster campaign for surgical services, a campaign she crafted with her audience in mind. “Certain personalities go into surgery,” she said. “Surgeons don’t have a super-long attention span for talking. That’s not a put-down; that’s just the way they are. You have to take your communication and make it work for them, so I made short sentences with bullet points.” Each poster in the campaign bore the slogan “For quality results, send tissue and fluids to microbiology.” One read: “Do the math. An effective culture requires six plates, one thio, and one Gram stain. If a swab yields only three bacteria, what are your chances for cultural success?”

The posters—bearing pithy headlines such as “Swabs don’t do the job”—went up everywhere from doctors’ lounge walls to the area above the urinals in surgical suite bathrooms, leading one surgeon to say to Dr. Cornish, “So, I see you’re putting your name on the bathroom walls.” As she told the audience, “I didn’t care, as long as he got the message.” Within just a couple of weeks, “we did start getting the right specimens,” she said. “It was pretty amazing. Physicians—not many of them have been in a laboratory. They don’t realize how few bacteria actually come back out of a swab. If you explain it to them, they’re more than willing to cooperate, for the most part. Eventually, you’ll show them you’re right.”

In addition to the poster campaign, Dr. Cornish initiated the creation of wound culture collection kits, which are available by request on all floors. “I found out they can’t have sharps on the floors anymore; they’re all locked up behind the nurses’ desk,” she said. “So we put together the kits”—which contain no swabs. In fact, by laboratory policy, swabs for mycobacterium or fungus cultures are no longer accepted at all.

She suggested that those in the microbiology laboratory alert clinicians to the facts that mycobacterial cultures require at least 1.5 ccs of fluid or tissue to inoculate one broth and two media tubes and perform an acid fast stain, while fungal culture requires one cc of fluid or tissue to inoculate two to three media tubes or plates and a fungal stain. In addition, for fungal and mycobacterial cultures, she recommends that when collecting tissue for culture, tissue be sent for histological exam as well, on the grounds that correlation of the histopathology and microbiology results is essential for correct interpretation. “You really do need tissue also,” she said. “You need to see what the background histologic pattern is.” Clinicians may also be unaware that fungus identified in the culture may be a colonizer or a contaminant, and that environmental mycobacteria can be colonizers but also can cause infection. Those mycobacteria may be seen in the tissue but not grown in culture, meaning they would be missed without the histopathological component.

Of course, no matter what educational efforts your institution undertakes, it’s unlikely you’ll be able to avoid ever receiving a bad specimen. Dr. Cornish recommended that if Gram stain shows that a specimen is of poor quality, such as by revealing the presence of squamous epithelial cells, the laboratory include a comment on the report to the effect that “Results of a Gram stain evaluation of this specimen suggest that superficial contamination is abundant and that culture will therefore provide misleading results. Large numbers of squamous epithelial cells were present, indicating surface contamination of the specimen.” And if the physician demands results for a specimen that Gram stain indicates is inappropriate? Then a comment such as “These results are reported by special request of the attending physician and may or may not reflect an accurate etiology of infection” is in order.

That said, simply adding disclaimer comments as a matter of routine is not a long-term solution, Dr. Rauch said; after all, disclaimers can’t cancel out the risks inherent in testing bad specimens. That’s why it’s vital to establish—and follow—good specimen acceptability policies across the board. She suggested that audience members ask themselves: “Does my lab have a ‘normalization of deviance’ culture? Or does practice equal policy?” “I do not take that for granted,” she said. “I’ve encountered many times someone just blatantly saying, ‘Oh, we just ignored that part [of a policy].’” That’s a recipe for bad habits, she noted.

One bad habit Dr. Rauch warned against: being pressured into testing so-called periclinical specimens, such as food or odd-looking substances on medical equipment. Her laboratory has been asked to test sediment at the bottom of an iced-tea bottle, a mysterious oily residue on a catheter, and, on one memorable occasion, a fish bone that had become implanted in the hand of a Vietnamese food processor. “The doctor was hoping to use the results of what the patient was exposed to as advance information in case the patient subsequently developed an infection,” she said. “I was very uncomfortable with that thinking. To me, that’s ‘CSI’ television mentality.” She did agree to culture the specimen, but only off-line. (The incident led to one technologist composing a commemorative limerick: “There once was a bone from a fish / That the doctor wanted placed on a dish / We said ‘No way’/ And ‘Have a nice day’ / But ultimately granted his wish.”)

Of course, few microbiology laboratories will be called upon to test a fish bone, much less write poetry about it. Still, the point remains: “If you are testing something you know to not be a quality specimen, and you have to issue a bill for that, that could be considered bad practice from a regulatory perspective,” Dr. Rauch pointed out. “Even if the clinician is vigorously demanding to take full responsibility, as they often do, they can’t. You always have a direct responsibility to that patient as well.”

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