Assessment of a cellular host response test to risk-stratify suspected COVID-19 patients in the Emergency Department setting

OBJECTIVE: Assess the IntelliSep Index (ISI) for risk stratification of patients presenting to the Emergency Department (ED) with respiratory symptoms suspected of COVID-19 during the pandemic. METHODS: An observational single-center study of prospective cohort of patients presenting to the ED during the early COVID-19 pandemic with respiratory symptoms and a CBC drawn within 4.5 hours of initial vital signs. A sample of this blood was aliquoted for performance of the ISI, and patients were followed for clinical outcomes. The study required no patient-centered activity beyond standard of care and treating clinicians were unaware of study enrollment and ISI test results. MAIN FINDINGS: 282 patients were included. The ISI ranges 0.1 to 10.0, with three interpretation bands indicating risk of adverse outcome: low (green), 0.1–4.9; intermediate (yellow), 5.0–6.2; and high (red), 6.3–10.0. Of 193 (68.4%) tested for SARS-CoV-2, 96 (49.7%) were positive. The ISI resulted in 182 (64.5%) green, 54 (18.1%) yellow, and 46 (15.6%) red band patients. Green band patients had a 1.1% (n = 2) 3-day mortality, while yellow and red band had 3.7% (n = 2, p > .05) and 10.9% (n = 5, p < .05) 3-day mortalities, respectively. Fewer green band patients required admission (96 [52.7%]) vs yellow (44 [81.5%]) and red (43 [93.5%]). Green band patients had more hospital free days (median 23 (Q1-Q3 20–25) than yellow (median 22 [Q1-Q3 0–23], p < 0.05) and red (median 21 [Q1-Q3 0–24], p < 0.01). SOFA increased with interpretation band: green (2, [Q1-Q3 0–4]) vs yellow (4, [Q1-Q3 2–5], p < 0.001) and red (5, [Q1-Q3 3–6]) p < 0.001). CONCLUSIONS: The ISI rapidly risk-stratifies patients presenting to the ED during the early COVID-19 pandemic with signs or suspicion of respiratory infection.