A biomarker assay to risk-stratify patients with symptoms of respiratory tract infection.

ABSTRACT

BACKGROUND: Patients who present to an emergency department with respiratory symptoms are often conservatively triaged in favour of hospitalization. We sought to determine if an inflammatory biomarker panel that identifies the host response better predicts hospitalization in order to improve the precision of clinical decision-making in the emergency department. PATIENTS AND METHODS: From April 2020 to March 2021, plasma samples of 641 patients with symptoms of respiratory illness were collected from emergency departments in an international multicentre study Canada (n=310), Italy (n=131), and Brazil (n=200). Patients were followed prospectively for 28 days. Subgroup analysis was conducted on confirmed COVID-19 patients (n=245). An inflammatory profile was determined using a rapid, 50-minute, biomarker panel Rapid Acute Lung Injury Diagnostic (RALI-Dx), which measures IL-6, IL-8, IL-10, sTNFR1, and sTREM1. RESULTS: RALI-Dx biomarkers were significantly elevated in patients who required hospitalization across all three sites. A machine learning algorithm that was applied to predict hospitalization using RALI-Dx biomarkers had an area under the receiver operating characteristic curve of 76±6% (Canada), 84±4% (Italy), and 86±3% (Brazil). Model performance in COVID-19 patients was 82±3% and 87±7% for patients with a confirmed pneumonia diagnosis. CONCLUSIONS: The rapid diagnostic biomarker panel accurately identified the need for inpatient care in patients presenting with respiratory symptoms, including COVID-19. The RALI-Dx test is broadly and easily applicable across many jurisdictions and represents an important diagnostic adjunct to advance emergency department decision-making protocols.