This study will analyze HostDx Sepsis results from whole blood samples collected from patients with suspected sepsis or at risk for sepsis in the surgical ICU

Inclusion Criteria:

Arm A

1. Age > 18 years
2. Suspected sepsis at the time of admission to the ICU
3. Direct admission from the ED to the ICU with suspected/proven sepsis.
4. Post-operative ICU admission after sepsis source control procedure
5. Inpatients admitted to the ICU from the ward with suspected sepsis onset.
6. Able to provide subject/proxy informed consent within 96h

Arm B

1. Age > 18 years
2. No suspicion of sepsis at the time of admission to the ICU but at high risk for subsequent sepsis onset
3. Non-trauma admission from the ED to the ICU
4. Post-operative ICU admission
5. Severe trauma admission from the ED (injury severity score >15, hemorrhagic shock, severe traumatic brain injury, and or severe chest trauma)
6. Inpatients admitted to the ICU from the ward for decompensation not initially suspected to be secondary to sepsis.
7. Able to provide subject/proxy informed consent within 96h

Exclusion Criteria:

1. Pre- or post-transplant patients
2. Patients admitted solely for airway monitoring, or vascular/flap check monitoring
3. Previous diagnosis of sepsis on index hospitalization.
4. Unable to provide informed consent within 96h
5. Previously enrolled in the present study.

Subjects admitted to the surgical ICU with suspected sepsis or at high risk for subsequent sepsis onset.