In late flu season, early signs of new tests’ impact

“In the wintertime, some doctors get into this habit where they start seeing influenza and then think every respiratory symptom is also flu without testing,” says Dr. Moore, a member of the point-of-care testing committees of the CAP and the Clinical and Laboratory Standards Institute. “They get into that blind spot where it could be Strep pneumonia, and they think it’s flu anyway. Well, they can run a test like this and when it’s negative they may think, ‘Let’s take a pause here. It may be a different etiological agent that is responsive to an antibiotic unlike the antivirals.’”

“In the past,” he adds, “rapids have had good specificity overall. You had confidence in a positive result, but not as much confidence in a negative result.”

Dr. Moore believes the 15-minute instrument time is fast enough to influence clinical decision-making in urgent care and physician offices. So does Susan Spanos, M(ASCP), microbiology supervisor at Everett Clinic, which has 11 walk-in outpatient facilities in western Washington state.

“There really isn’t anything else on the market that is this fast,” she says. “That’s what it’s all about, so that the physician can have the results quickly, make a decision, prescribe what they need to prescribe, and the patient’s on their way. And patients want that as well.”

Each clinic has at least one Alere i system, just a few steps down the hall from the exam rooms. Phlebotomists who are overseen by a medical technologist perform the tests, Spanos says. For influenza A, compared with culture, the Alere i test has a sensitivity of 97.9 percent and specificity of 86.2 percent, the company says. For influenza B, the test has a sensitivity of 92.5 percent and specificity of 96.5 percent.

Everett Clinic had used rapid antigen testing before it adopted the Alere rapid molecular flu test.

“The doctors were used to getting a result within 15 minutes. That’s why they wanted to still hit that mark so they could make real-time decisions about treatment,” Spanos says. “But this is a much more sensitive test and we have picked up far more influenza than we did by rapid antigen.”

When Spanos led implementation of the new flu testing method during the 2014–2015 flu season, she tracked test accuracy and clinical decision-making before and after the Alere test went live. Of 56 specimens tested for flu, 32 were positive by the Alere test while the rapid antigen method found only 11 to be positive.

In the period before implementing the Alere test, 18 of the 56 patients were prescribed antibiotics. But half of those patients, based on testing using the Alere and specimens sent to the state public health laboratory, were positive for influenza and thus got the wrong treatment.

Spanos also examined 53 patient charts from the period immediately after Everett Clinic went live with the Alere rapid flu test. Of those 53 patients, 12 were prescribed antibiotics and only four had a positive flu test. In each of those cases, there were other clinical factors that may have justified the antibiotic prescriptions, Spanos says.

No comprehensive cost comparison is in the offing, but Spanos and her colleagues believe the rapid molecular flu test makes financial sense.

“This test is more expensive than the rapid antigen test, as would be expected. But we had discussed this, and the tradeoff is better for patient care. And being able to know for sure that a patient has influenza, and that they can be treated, is a big deal considering that people die of influenza.”

A third rapid molecular flu test will enter the market next year, pending regulatory approvals for Cepheid’s new GeneXpert Omni point-of-care system. The Xpert Flu+RSV Xpress is expected to have a run time of around 30 minutes. A Strep A test also will be available on the menu for the system. The flu/RSV test already is available, and CLIA-waived, on the GeneXpert I system; it has an instrument time of 60 minutes.

Cepheid CEO John Bishop says laboratories may want to wait on his company’s product because, first, it offers simultaneous detection of RSV, which is vital for pediatric and geriatric patient populations. (Roche has submitted a flu/RSV POC test for FDA clearance and CLIA waiver, a company spokesman says.) Bishop adds that PCR is more accurate than the isothermal method employed in the Alere i. “At the end of the day, time to result is irrelevant if you’re getting inaccurate results,” he says.

A few minutes’ difference in turnaround time may not mean much in real-world clinical practice, Bishop argues, noting the Omni system will feature wireless transmission of results. That means even if the patient is already out the door it will be painless to send the results to the patient and physician and enable the clinician to take quick action in changing the electronic prescribing order, if needed.

For clinicians who want to order a larger respiratory panel, a relatively new option available this flu season is Nanosphere’s Verigene Respiratory Pathogens Flex. Called RP Flex for short, the panel was cleared by the FDA in September 2015 and allows for flexible ordering of 16 target respiratory pathogens with a 3.5-hour run time.

Northwest Community Hospital, located in the Chicago suburb of Arlington Heights, implemented the RP Flex in mid-February.

“A huge plus for us was the flexibility of it,” says Jason Weiss, DO, Northwest’s medical director of molecular and cytopathology. “As a community hospital, we have our own lab and we’re not affiliated with a large hospital group. . . . Our budget’s a little bit tighter because we’re a standalone hospital. But we wanted to provide the up-to-date care that the surrounding hospitals were.”

The hospital also uses the Alere rapid flu test.

“Our algorithm is that if these patients aren’t that sick, our clinicians look to see if they have the flu,” Dr. Weiss says. “We do the Alere and we get the results back very quickly. We have those at our [outpatient] treatment centers, and they are available for our emergency room patients too. And if the patients are really sick, ideally, we would like the clinicians to order the Nanosphere. Those patients are getting admitted anyway, so the more expanded menu of results helps in providing appropriate care for the patient.”

With the RP Flex, Northwest Community physicians can order in these combinations: flu alone, flu and RSV, the three Bordetella bacterial pathogens, or the rest of the respiratory pathogens as one order set. While the multiplex test simultaneously detects any of the 16 pathogens present in a sample, the results are revealed and interfaced only for those analytes the clinician requests. Between 10 and 15 percent of all the samples run on the RP Flex have been for the expanded respiratory panel, Dr. Weiss says.

Some laboratory professionals have raised ethical questions about the RP Flex, objecting to the quandary arguably created when the laboratory performs a test but does not share the result with the clinician because it was not actually ordered.

Dr. Weiss does not share that concern.

“If someone sends us a tube of blood, we could run every test in the book on it. We only run what you order,” he says. “Clinicians can always call us and unmask those results. The test isn’t finished, in my opinion, because the results aren’t available.”
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Kevin B. O’Reilly is CAP TODAY senior editor.