Clinically Significant Monocyte Biomarker for Differential Diagnosis of COVID-19 Pneumonia in the Emergency Department

Abstract

To determine basic patient characteristics and biomarkers to help in the early diagnosis of Coronavirus disease 2019 (COVID-19) pneumonia in patients with pneumonia who visited the emergency department (ED). This retrospective study evaluated patients diagnosed with community-acquired pneumonia (CAP) or COVID-19 pneumonia in the ED at four tertiary medical centers between February 1 and March 31, 2020. Parameters related to the differential diagnosis between CAP and COVID-19 were investigated. Clinical characteristics and laboratory results of biomarkers were analyzed. In total, 81 patients presented to the ED with COVID-19 pneumonia. Multivariate logistic regression analysis showed that monocyte count [odds ratio (OR): 0.996; 95% confidence interval (CI): 0.994–0.999] and pneumonia severity index (PSI) [OR: 1.025; 95% CI: 1.002–1.049] were associated with diagnosis of COVID-19 pneumonia. The area under the curve comprising the combination of monocyte and PSI was 0.789. Differential diagnosis of COVID-19 pneumonia from pneumonia patients who visited the ED can be made by monocyte count and PSI score.