Evolving swabbing practices for COVID-19 in a New Zealand emergency department during the early stages of an emerging pandemic

Abstract

Objective: To review if tests for suspected COVID-19 were performed according to the Ministry of Health (MoH) case definitions, identify patterns associated with testing outside of the case definition, and discuss the potential impacts on hospital services.

Methods: This was a retrospective audit of patients presenting to the Wellington Hospital ED between 24 March 2020 and 27 April 2020 who were swabbed for COVID-19 in ED. Swabs were audited against the March 15th and April 8th MoH COVID-19 case definitions.

Results: Five hundred and thirty-six COVID-19 swabs for 518 patients were taken during the study period. There was poor alignment of testing with the March 15th case definition, with only 11.6% of the 164 swabs taken during this period meeting the case definition. Of the 145 swabs that did not meet the case definition, the majority (n = 119, 82.1%) met symptom criteria only. Alignment of testing with the wider April 8th case definition was much higher with 88.2% meeting criteria. Factors associated with being swabbed despite not meeting the case definitions included fever >38°, a diagnosis of cancer, subsequent hospital admission, and for the March case definition only 'contact with a traveller'.

Conclusion: There were associations found between testing outside of criteria and specific variables potentially perceived as high-risk. Poor alignment of testing with case definitions can impact hospital services through the (mis)use of limited laboratory testing capacity and implications for resource management. Improved communication and feedback between clinicians and policymakers may improve case definition implementation in a clinical setting.

Keywords: COVID-19 testing; clinical audit; emergency medicine; pandemic; public health.