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Roche Rapid Flu MDx Test Shown to Impact Patient Care in ER

AUSTIN, Texas (GenomeWeb) – Roche's Cobas Liat molecular flu assay is a rapid, adaptable, and sensitive assay that can impact patient care in the emergency room setting, according to the results of a physician behavior study presented at the Association for Molecular Pathology annual meeting, held here this week.

In addition, there is early evidence that the test may also be cost-effective for emergency departments when taking into consideration the cost savings associated with eliminating unnecessary therapeutic administration or patient admission to the hospital.

At a corporate-sponsored presentation at AMP on Wednesday, Glen Hansen, director of clinical microbiology and molecular diagnostics at Hennepin County Medical Center in Minnesota, discussed the results of the CLADE ("clinical laboratory and diagnostic effectiveness") study — a prospective observational cohort to determine the impact of Roche's Cobas Liat Influenza A/B assay on clinical decision making in the emergency department setting.

Roche's assay is a real-time PCR-based test designed to detect and differentiate influenza A and B in about 20 minutes, or about as fast as currently used immunoassays, but with the increased sensitivity afforded by nucleic acid testing. It runs on the Cobas Liat analyzer, a small benchtop platform that accepts various Liat test cartridges. The Liat analyzer received a CLIA waiver in May along with a Strep A assay, and the flu A/B assay received a CLIA waiver in September.

In his AMP presentation, Hansen noted that his lab at HCMC implemented the Liat Analyzer and flu assay prior to the 2015 flu season. Concurrent with the CLADE study, his lab also compared the analytical performance of the flu assay to influenza results from the GenMark eSensor Respiratory Viral Panel.

The group presented very early results from the analytical comparison in a poster at the Clinical Virology Symposium in May, and presented additional results from both the analytical comparison and CLADE study at the American Association for Clinical Chemistry annual meeting in July.

Hansen said at AMP that both studies have now been completed, noting that HCMC investigators found that the sensitivity of Cobas Liat FLu A/B is around 96 percent, while its specificity is around 98 percent.

However, Hansen added, "It's fine to show sensitivity and specificity, but does any of this testing matter at all? How do we show [hospital] administrators?" The CLADE study, he said, was designed to address these questions.

The study enrolled 314 patients over three months during the 2015 flu season, with 24-hours-a-day, 7-days-a-week study enrollment. A five-page survey was administered to both emergency department physicians and patients with various questions about patient symptoms, diagnosis, patient management, antibiotic or antiviral administration, hospital admissions, and patient satisfaction. The researchers ended up with a cohort of 150 cases.

Importantly, to overcome the inherent biases of a survey study, changes in patient management were noted by providers and verified by retrospective chart review, i.e. the investigators had to see documentation in the electronic medical records for changes in patient management.

The study revealed that 57 percent of physicians reported that the Cobas Liat test results changed their patient management, while 43 percent reported that the test had no effect. The vast majority of changes occurred in patients who were negative for flu. For example, 53 percent of those physicians changed their antiviral or antibiotic stewardship, underscoring the potential of Cobas Liat as a rule-out assay. Meantime, 17 percent of patient management changes resulted in the hospital admission or discharge of a patient; and 19 percent resulted in changes to procedures or lab test orders.

Hansen and colleagues have also undertaken an economic benefit analysis of using the Roche test for flu diagnosis at HCMC. "We wanted to use a healthcare economic model to show its value … and it needs to be framed in a way that makes sense to the provider," Hansen said.

He noted that the published mean cost per patient stay for diagnosis of pneumonia is about $10,000. Over a 65-day period at HCMC, 15 such cases came through the ER, for a total estimated cost of $150,000 using traditional diagnosis and treatment means. Added to this is the cost of a five-day course of Tamiflu, administered to 33 patient cases for a total of $3,300.

Hansen said that his group's economic analysis of the Cobas Liat flu assay is still in the early stages, but that it seems that it will prove to save HCMC money while providing patient care at least as equally effective as prior diagnosis methods and patient management.

However, he stressed that "the price point of these instruments is going to be really important. How many of these instruments will [a lab] need for sufficient throughput?"

Roche has not publicly disclosed the cost of the Liat Analyzer or flu tests