Influenza Testing at Point of Care Improves Hospital Triage and Patient Outcomes

Tristan Clark, MD

Patients presenting to hospitals with acute respiratory illness who received point-of-care, molecular-based testing of influenza were more likely to have influenza accurately diagnosed and receive efficient triage for appropriate isolation and timely antiviral treatment, than those receiving routine clinical care with centralized laboratory testing.

“Influenza often remains undiagnosed in patients admitted to hospital due to the absence of universal testing for influenza in patients with acute respiratory illness and the inaccuracy of testing based on clinical suspicion of infection,” observed Tristan Clark, MD, School of Clinical and Experimental Sciences Faculty of Medicine, University of Southampton, and colleagues.

Although there is ample evidence that point of care testing (POCT) with high quality PCR assay can provide accurate results much quicker than when samples are routed to centralized labs, Clark and colleagues indicate that there have been few studies that measure the impact of that difference on patient management and clinical outcomes.

“Molecular POCT for influenza in acute admissions allows confident, real-time decision making,” Clark told HCPLive. “This is associated with a wide range of benefits compared to lab testing where clinical decisions have to be made based on clinical assessment, which is inaccurate, and then adapted when results come back many hours later.”

To characterize and quantify such differences between point of care PCR influenza testing with test-and-treat strategy vs routine care and centralized laboratory testing, Clark and colleagues conducted an open-label, randomized controlled trial at 2 hospitals in the UK. 613 patients presenting with acute respiratory illness were enrolled between December 12, 2017 and May 3, 2019 to either influenza POCT-guided treatment protocol (n = 307), or routine care with centralized lab testing (n = 332).

The primary outcome was the proportion of patients infected with influenza who were treated appropriately with neuraminidase inhibitor antivirals per hospital protocol within 5 days of admission. In addition, the investigators evaluated time to initiate the antiviral, utilization of isolation facilities, and clinical outcome.

The investigators reported that 99% of the 100 patients with influenza in the POCT group were accurately diagnosed on admission compared to 59% of the 102 with influenza receiving routine clinical care. The 99% in the POCT group diagnosed with influenza were also given antiviral treatment within 5 days of admission, versus 62% of those with influenza in routine care. The median time to initiate antiviral treatment was 1 hour in the POCT group vs 6 hours in the routine care group. 70% of those who had influenza in the POCT group were isolated to single-room accommodation vs 38% of those with influenza receiving routine care.

There were 19 adverse events among patients with influenza in the POCT group, and 34 events in those with influenza in the routine care group. In addition, 2 patients with influenza receiving routine care died, and no deaths occurred in the POCT group.

The study did not evaluate the thoroughness of diagnostics besides the influenza testing. For example, Clark pointed out, “although not effective on its own, as patients can have influenza and bacterial infection, molecular POCT for influenza can be combined with serum biomarker-based strategies such as CRP or procalcitonin to improve antibiotic stewardship and reduce unnecessary antibiotic use.”

Clark also suggested that these POCT study findings are appropriate to consider in light of the current COVID-19 pandemic, “where the need for accurate results is recognized to identify cases coming into hospital and prevent transmission.”

“Most molecular POCT platforms now have, or are developing multiplex assays that can detect influenza and SARS-CoV-2,” Clark commented.

The study, "Clinical Impact of a Routine, Molecular, Point-of-Care, Test-and-Treat Strategy for Influenza in Adults Admitted to Hospital (FluPOC): A Multicentre, Open-Label, Randomised Controlled Trial," was published online in The Lancet Respiratory Medicine.