CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Dr. Schreckenberger
“As a lab director, I have a real problem with saying, ‘Let’s use less sensitive tests.’ I think that physicians should know what’s out there and they should use that information, along with their clinical judgment and with their knowledge of what’s going on with the patient,” said Dr. Schreckenberger, clinical microbiology director at Loyola University Medical Center, Maywood, Ill. “To me, it’s a slippery slope to say that a molecular test is not good because it results in false-positive test results. It is not a false-positive if the target is present in the sample—for example, herpes virus. It’s just a matter of whether it’s connected to infection.”
In an interview, Dr. Newton says he would frame the issue differently.
“The question is in what clinical scenarios is it most appropriate to utilize molecular,” he says. “It is analytically more sensitive, but I think the issue is specificity from a clinical perspective. And there are a lot of examples where maybe it is analytically too sensitive and you lose some clinical specificity.”
Objections to molecular methods for detecting viral pathogens are not always about sensitivity, Dr. Newton adds. The Michigan clinical microbiology laboratory had discontinued direct fluorescent antibody testing for respiratory virus infections when it implemented molecular, but it maintained DFA for detection of herpes simplex and varicella zoster viruses from lesions.
“As the assays became available and validated in our labs for PCR for herpes and varicella, our desire was to discontinue DFA,” he says. With a desire to avoid the implement-first, ask-later approach, Dr. Newton shared the plan with heavy clinician users of this testing.
“The pushback really revolved around turnaround time,” he says. Accustomed to two-hour TATs with DFA testing, “once-a-day molecular testing wasn’t something they were super excited about.”
In response, Dr. Newton and his colleagues have changed their approach, switching to Focus Diagnostics’ 3M Integrated Cycler, a platform “that is much more amenable to more frequent, small batches during the day. We’re in the process of going live with herpes and varicella on that platform…so we can do multiple runs during the day.”
The 3M Integrated Cycler’s analytical run time for Focus’ HSV and VZV assays is about one hour, Dr. Newton says. The agreement with clinicians is to perform two runs, one in the morning and one in the afternoon, seven days a week.
At the Cleveland Clinic, HSV for lesions is one of the few areas in which the virology laboratory still uses a nonmolecular method, Quidel’s ELVIS HSV Test System. Gary W. Procop, MD, MS, who directs molecular microbiology, virology, mycology, and parasitology at Cleveland Clinic, says they still do traditional culturing for enterovirus other than cerebrospinal fluid and for CMV other than blood.
“That’s about it,” Dr. Procop says. “Every once in a while, we’ll do a test-of-cure culture, particularly in an immunocompromised patient whose symptoms have not resolved.”
“The real paradigm shift,” he adds, “is not only the multitude of molecular virology tests available, but that many of them are available for platforms that are very simple to use, platforms that can be used for a variety of different pathogens, and that can be implemented in 200-bed hospitals. In the past, tests that could not be done locally were referred out. Now, many of these tests can be performed locally in smaller-sized hospitals with high-quality results.”
Unlike Michigan, Cleveland Clinic does not send out all test orders requesting culture.
“We’ve retained some ability. Many places would just make it a send-out,” says Dr. Procop, professor of pathology at the Cleveland Clinic Lerner College of Medicine. “Some of these, like the influenza culture, have been retained as a lab-order only. It’s only going to be placed if the doctor calls us, explains the clinical need and rationale, and then it may get approved. If we put all the testing possibilities on the test menu order, some busy person is going to check all the boxes. There’s a lot of utilization management that goes into these efforts.”
Dr. Procop
While lacking hard data on how far laboratories performing virology testing across the country have gone in giving up traditional testing methods, Dr. Procop says commercial development is making the biggest difference in speeding the transition.
“The more turnkey that vendors make their product, the wider the distribution it will have,” he says. “For many of these tests that we have been doing for years—not just here but at other academic medical centers—you had to have people to design the primers and the probes and construct the assays. But poor old St. Elsewhere hospital didn’t have that. They also couldn’t sustain the cost infrastructure.
“What’s really been a change in the development and marketing from numerous manufacturers is that many of these companies followed Cepheid’s lead of having single-use cartridges. You do this, and you throw it away. It all comes prepared. You don’t need basic scientists there, and it’s FDA approved.”
“The traditional virology laboratory,” Dr. Procop concludes, “has been transformed to a molecular virology laboratory.”
Navigating this sea change, Michigan’s Dr. Newton insists, requires a cooperative style from the laboratory.
“There’s very little in the way of things that we can’t do [technologically],” he says. “If you have the resources, you can do a lot, but you have to have a willingness to keep patient care at the front of your decision-making process. It’s about what’s best for the patients, not what’s convenient or easy for the laboratory.”
“Here I feel fortunate,” Dr. Newton adds, “that I don’t have to battle too much with administrators, and I don’t have to battle too much with our clinical colleagues. I have a great relationship with my colleagues. I don’t always get what I want. And they don’t always get what they want.”
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Kevin B. O’Reilly is CAP TODAY senior editor.