It's that time of year again -- time for the general public and healthcare professionals alike to start thinking about three little letters with a potentially big impact: F-L-U.
The Centers for Disease Control and Prevention (CDC) reports that between 135 and 139 million doses of the influenza vaccine are being produced this season, with most of the supplies ready by September and October. The CDC urges everyone older than 6 months of age to get a flu vaccine by October.1
This season's flu vaccine is made from these three viruses, according to the CDC:
- an A/California/7/2009 (H1N1)pdm09-like virus;
- an A(H3N2) virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011;
- a B/Massachusetts/2/2012-like virus.2
A quadrivalent vaccine also contains these viruses along with a B/Brisbane/60/2008-like virus, the CDC says.2
Although no one can predict what type of flu season will occur, all healthcare facilities need to be ready to not only provide the seasonal flu vaccine but to treat flu in patients. This, of course, includes the laboratory.
Laboratory professionals are already gearing up for the 2013-2014 season. Read on to find out how two pediatric hospitals are getting ready to treat their young patients.
Multiple Testing Options
Even though the flu season itself is unpredictable, one laboratory supervisor has a lab-related flu prediction: "In terms of new trends in flu testing, I think more labs will be using polymerase chain reaction (PCR) to detect or confirm a diagnosis of flu this season," explained Stephanie Bledsoe, MT(ASCP), Virology Lab Technical Supervisor at St. Louis Children's Hospital (SLCH). "The advent of user-friendly PCR test platforms that are 'sample in/answer out' has made PCR accessible for more labs. But in general, I think most labs will still use rapid antigen tests to quickly screen patients for the flu. How the negative results are confirmed, when indicated, may shift from viral culture to PCR due to the speed with which results are available."
At SLCH, laboratory professionals use the BioFire FilmArray Respiratory Panel. They are no longer offering viral culture or direct fluorescent antibody straining to detect influenza, Bledsoe said. "During flu season's peak, the Emergency Unit (EU) staff will perform 800-1,000 rapid flu tests in a month . We believe our rapid antigen test for influenza serves as an excellent screening tool in the EU setting during peak season," she added, noting that the test is not performed outside of peak season. "At the same time, the virology lab can expect to test an equal number of specimens using the FilmArray respiratory panel."
The BioFire test is performed 24/7 in the virology lab, with a median TAT of 74 minutes for SLCH specimens, Bledsoe noted. The testing is also offered to outreach clients with a median TAT of 96 minutes.
For patients who don't warrant a comprehensive respiratory panel, the virology laboratory also offers the Focus Diagnostics Simplexa Direct Flu A/B & RSV PCR assay. The samples are batched and run every hour, with results taking about an hour, Bledsoe said. The test "is an excellent option if the care provider is primarily interested in simply ruling out flu and RSV and does not need a complete respiratory pathogen panel," she added.
To keep staff abreast of flu development, data is posted to the laboratory section of the SLCH website on a weekly basis. Internal emails are also sent to various department leaders. "I think community physicians who view the weekly report find it useful to note when we start seeing an uptick in influenza activity before things really begin to take off," Bledsoe said. "Because our lab provides testing for not only SLCH, but also many other area hospitals, the report allows physicians to see the wide variety of respiratory pathogens that are circulating in the greater St. Louis area in general."
An Emphasis on More than Just Flu Testing
At Seattle Children's Hospital, laboratory professionals don't just focus on testing for flu when a patient presents with suspicious symptoms. They test for acute respiratory illness with a variety of pathogens, explained Joe Rutledge, MD, pediatric pathologist. "The number of pediatric patients with respiratory syncytial virus (RSV) is much higher than patients diagnosed with the flu," he said. Laboratory professionals at Seattle Children's also use the BioFire FilmArray Respiratory Panel to accomplish this.
Not to say that that flu isn't also a concern, however. The hospital has time to prepare once flu season picks up-a slight advantage to being on the West Coast. "Seattle lags a few weeks behind the rest of the country, so we have a few weeks of prediction from the activity on the East Coast," Dr. Rutledge said. He recalled that last year's testing volume for the respiratory panel, including both influenza A and B, was about 5,000 tests.
Seattle Children's boasts the fastest turnaround (TAT) time in the nation for producing respiratory virus results. Among the reasons why the hospital's TAT is so speedy: "the test requires only 65 minutes machine time and five minutes hands-on time to analyze, and the testing occurs in the 24/7 core laboratory, which is designed for rapid turnaround of all results," Dr. Rutledge said.
Getting test results back to parents of sick children is so crucial, no matter if it's the flu or a respiratory illness. "We want to move patients through the Emergency Department faster and leaving with a definitive plan," Dr. Rutledge told ADVANCE. "Hardly anyone enjoys waiting in an Emergency Department with an ill child. We also want to provide a definitive diagnosis that may prevent a more aggressive diagnostic workup."
Amanda Koehler is a freelance writer.
CDC. Seasonal influenza (flu). Available at: www.cdc.gov/flu
. Last accessed Sept. 8, 2013.
- CDC. What you should know for the 2013-2014 influenza season. Availalbe at: www.cdc.gov/flu/about/season/flu-season-2013-2014.htm. Last accessed Sept. 8, 2013.