The mortality rate of sepsis remains as high as 30 to 40%. Early diagnosis and treatment of patients with sepsis reduce mortality significantly. The most commonly used biomarkers in clinical practice are C-reactive protein (CRP) and procalcitonin (PCT). In terms of exploring new diagnostic tools of sepsis, monocyte distribution width (MDW) was first reported in 2017. It was reported as part of the white blood cell (WBC) differential count. MDW greater than 20 and abnormal WBC count together were reported to provide a satisfactory accuracy. The area under curve (AUC) in predicting sepsis-2 is 0.852. It was proposed as a novel diagnostic tool of sepsis in the emergency setting. Nonetheless, the performance of MDW compared with the conventional biomarkers remained unknown. The aim of this study was to compare the diagnostic accuracy of MDW and PCT on sepsis in the emergency department.

Subject Inclusion Criteria

• Adult ≥20 years) subjects presenting to the ED with the chief complaints of fever, altered consciousness, hypotension, and dyspnea. CBC with differential testing performed, at presentation as part of their standard medical care.
• Subjects who have signed Informed Consent.

Subject Exclusion Criteria

• Previously enrolled in this study (i.e. subjects may not be enrolled more than once in this study)
• Subjects discharged from the ED <72 hours
• Pregnant women
• Subjects not able to understand or sign Informed Consent

Based on a target of 75% sensitivity and lower limit of 65%, a minimum of 63 (will target 100) septic patients would be required. Higher numbers may be enrolled in the study to ensure adequate representation of sepsis cases. Given the estimated prevalence of the disease in the emergency department population (5-10%%), the number of non-septic patients is predicted to be significantly higher than septic. Based on the estimated prevalence of subjects who present and have blood draw, a minimum of 100 non-septic cases will be collected.