Background: Seasonal influenza is a burden for emergency departments. The aim of this study was to investigate whether point-of-care (POC) PCR testing can be used to reduce staff sick days and improve diagnostic and therapeutic procedures. Methods: Using a cross-over design, the cobas® Liat® Influenza A/B POC PCR test (Liat) was compared to standard clinical practice during the 2019/2020 influenza season. All adult patients (aged ≥18 years) with fever (≥38°C) and respiratory symptoms were included. Primary endpoints were prevalence of influenza infections in the ED and staff sick days. Secondary endpoints were frequency of antiviral and antibacterial therapy, time between admission and test result or treatment initiation, patient disposition, ED length of stay (LOS) and for in-patients mortality and LOS. Nurses were interviewed about handling and integration of POC testing. The occurrence of SARS-CoV-2 infections coincided with the second half of the study. Results: A total of 828 patients were enrolled in the study. All 375 patients of the intervention group were tested with Liat, 103 of them (27.6%) tested positive. During the intervention period staff sick days were reduced by 34.4% (p=0.023). Significantly more patients in the intervention group received antiviral therapy with neuraminidase-inhibitors (7.2% vs. 3.8%, p=0.028) and tested patients received antibiotics more frequently (40.0% vs. 31.6%, p=0.033). Patients with POC test were transferred to external hospitals significantly more often (5.6% vs. 1.3%, p=0.01). Conclusion: We conclude that POC testing for influenza is useful in the ED, especially if it is heavily frequented by patients with respiratory symptoms.

IntroductionSince the outbreak of COVID-19 there has been an unprecedented effort from the scientific community to develop tools to help tackle this crisis. According to the Foundation for Innovative New Diagnostics (FIND; 18 March 2021) there are 1025 commercialized SARS-CoV-2 assays currently available and an additional 98 in development, including 655 immunoassays and 437 molecular assays.1 Early in the pandemic, molecular testing using nucleic acid amplification tests (NAATs) became the pillar of COVID-19 diagnostics. Since then, the development of antigen tests, immunoassays, point-of-care, and centralized options means there are now choices to be made as to how, when, and where to deploy these technologies and many guidelines have been developed, often based on Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) guidance.2-4 However, with the rapid emergence of new technologies and new scientific data, these guidelines are very fluid and subject to change. Furthermore, while NAATs are the most sensitive diagnostic tool for COVID-19 infection,3-5 the global demand for diagnostic testing is still such that the use of labour-intensive, specialist techniques needs to be carefully considered.The aim of this review is to provide an international evaluation of real-world testing needs and to define: settings where the ‘next best’ alternatives to NAATs are appropriate; settings where NAATs may not be the best option; how to manage antigen test results; and how to manage negative NAAT results where there is still a strong clinical suspicion of COVID-19. We will further aim to set out the key considerations for defining a testing strategy. Table 1 demonstrates that each testing strategy provides different information on infection status and has different performance metrics, so the right option for the right setting needs to be carefully assessed. Here we also discuss the common challenges facing clinicians and laboratorians when interpreting and supplying COVID-19 diagnostics and provide insights into what will be needed next.Table 1. A summary of the diagnostic testing methodologies for COVID-19.