The purpose of this study is to confirm the clinical validity and the performance of the Monocyte Width Distribution (MDW) parameter to detect the development of sepsis in a prospective study of Emergency Department (ED) adults who have blood draw including Complete Blood Count with differential (CBC-DIFF) ordered upon presentation in a Spanish & French hospital and to verify cut-off for Tri-potassium ethylenediaminetetraacetic acid (K3EDTA).

To confirm the clinical validity and performance of the Monocyte Width Distribution (MDW) parameter to detect the development of sepsis in a prospective study of ED adults who have blood draw including CBC with Differential ordered upon ED presentation. Septic patients are identified as those with values equal to or above the MDW threshold and non-septic patients are those with MDW values below the threshold. As the anticoagulant used at the sites is K3EDTA, the cut-off value will be assessed using sepsis cases and all corresponding non-sepsis to confirm optimal cut-off.

To explore the added value of this parameter in a patient diagnostic pathway that includes the use of procalcitonin (PCT) or C reactive protein (CRP) for the identification of septic patients All enrolled subjects will have PCT/ CRP assay performed per protocol Plasma will be aliquot and stored frozen for subsequent testing at Beckman Coulter for other sepsis biomarker tests (additional PCT& CRP tests and interleukin-6 (IL-6) on the sponsor's devices

Inclusion Criteria:

• CBC-DIFF upon presentation
• Adults (18-89) of all races & ethnicities
• Signed Informed Consent

Exclusion Criteria:

• Previously enrolled
• Incomplete Informed Consent
• Subject discharged <4 hours from presentation
• PCT or CRP not performed per protocol
• Pregnancy
• Prisoners
• Subjects Under Custody or Guardianship

All adults with suspicion of infection who present to the Emergency Department and for whom a CBC-DIFF is ordered upon presentation