That Friday in 2009 began like any other day for the North Shore-LIJ Laboratories, the core diagnostics facility for the North Shore-Long Island Jewish Health System, one of the largest hospital networks in the New York metropolitan area.
The day before, however, some 150 students at New York's St. Francis Preparatory School in Queens began showing the symptoms of a respiratory illness suspected to be H1N1 influenza, or swine flu, prompting public health officials to launch an investigation into a possible outbreak.
"We were the epicenter of the New York City outbreak," says Christine Ginocchio, chief of infectious disease diagnostics in the pathology department at North Shore-LIJ.
"On Friday, April 24 — I remember the day quite well — we went from winding down flu season with about 150 flu tests per day … to doing 1,000 tests per day on Monday," Ginocchio says. "We were overrun."
At the time, Ginocchio's laboratory — like many other diagnostic labs in the US — was using rapid antibody testing to diagnose flu. And while the test is generally a quick and reliable way to diagnose standard influenza infections, it falls short as a tool to diagnose H1N1.
"One of the problems, of course, was that [H1N1] was a new viral variant … and many of the rapid tests had a poor sensitivity for detecting the virus because it was a new strain," Ginocchio says. "With influenza viruses, as with other RNA viruses, this is a major problem — they change very quickly."
Enter molecular testing — specifically, Luminex's xTag Respiratory Virus Panel, which can simultaneously amplify nucleic acids from several respiratory viral targets and detect the resulting PCR products using a highly multiplexed, bead-based system.
North Shore-LIJ had already validated the Luminex platform when the outbreak occurred, and it immediately instituted the system, which "really became a savior for us," Ginocchio says. "It was really an invaluable tool [for the outbreak], and we've been using it ever since as the mainstay of our respiratory virus testing."
In the meantime, however, molecular testing has evolved to the point where molecular testing, particularly quantitative real-time PCR, has become a de rigueur tool for diagnosing infectious diseases — and now core laboratories are looking for ways to move molecular testing to the point of care and eliminate slow and inefficient centralized testing.
Luminex's test, she notes, is not conducive to such a scenario. "It's a very complex test and certainly would not be done in many local hospitals," she says.
As such, North Shore-LIJ has now begun decentralizing its respiratory virus testing using the FilmArray system and respiratory panel assay from BioFire Diagnostics, which changed its name from Idaho Technology in August.
The FilmArray platform currently detects and distinguishes between 20 respiratory pathogens, viral and bacterial, by automatically extracting and purifying nucleic acids from an unprocessed sample, amplifying pathogenic nucleic acids using a two-step nested PCR process, and comparing endpoint melting curve data to generate a result.
The system is highly accurate, covers most of the respiratory pathogens frequently encountered in a hospital setting, and, importantly, can provide a result in about an hour and a half with two minutes of hands-on technician time, Ginocchio says.
"Now, running a [FilmArray] on a patient in the [emergency department] … the local community hospitals and the tertiary care centers can provide a very comprehensive, accurate result very early on," she adds.
Ginocchio says that FilmArray is an early example of how molecular testing will likely move from "sophisticated core laboratories … back out to the community, to the point of care, where a lot of it needs to be."