Determine the utility of biomarkers measured in blood and body fluid (stool, saliva, tracheal aspirate) when combined with clinical data, for predicting sepsis phenotypes that are associated with poor clinical outcomes. We hypothesize that resistin is a biomarker which provides critical prognostic information when used in conjunction with standard clinical data, in patients with sepsis and septic shock.

Day 1 Sample Collection: 20ml of blood for chemical and genetic biomarker analysis. ≤1ml of saliva, stool, and tracheal aspirate for inflammatory marker analysis. Quadratus lumborum muscle size measurement and CT abdomen correlation. If not part of routine care, additional blood tests for cell differential, procalcitonin, and inflammatory markers.

Electronic Medical Records (EMR) Data: APACHE II and SOFA severity scores. Demographics, vital signs, inflammatory markers, organ dysfunction markers, and various blood chemistry values.

Days 2-3 Daily Documentation: Record the most abnormal value for the same parameters as Day 1.

Days 3-5 (Once) Sample Collection: Repeat of blood, saliva, stool, and tracheal aspirate collection. EMR data access for severity scores and other clinical parameters.

Days 5-6 Daily Documentation: Continued recording of the most abnormal values for clinical parameters.

Days 7-10 (Once) Sample Collection: Repeat of blood, saliva, stool, and tracheal aspirate collection. Measurement of muscle size and CT correlation. EMR data access for the same parameters as earlier.

Day 14 (or Discharge) Final Sample Collection: 20ml of blood and other samples, with no more than 1 ml/kg of blood collected over the entire study.

EMR and Clinical Data: Collection of severity scores, vital signs, inflammation markers, organ dysfunction markers, and other clinical variables.

Day 30, 3 Months, 6 Months, and 1 Year Long-term Outcomes: EMR review for clinical outcomes such as date of death, re-hospitalization, persistent critical illness. Phone interviews to gather subjective data about the post-hospitalization course and complications.

Inclusion Criteria:

1. Adults (age ≥ 18 )
2. gender: male or female
3. Cognitively intact or impaired patients, given that sepsis may cause a certain degree of cognitive dysfunction in patients. All patients in the control group (no sepsis) will be cognitively intact
4. Clinical suspicion for sepsis (except for control/comparison group for whom infection is NOT a current concern)

Exclusion Criteria:

1. Patients with hematologic malignancies
2. Pregnant women
3. Patient/surrogate is not fluent in English and no translation services are available
4. Long-term immunosuppressive therapy
5. Prisoner

Patients in the intensive care unit (ICU) who meet critera for sepsis, as defined by the Sepsis-3 criteria and who are not excluded by any of the exclusion factors listed in the "Eligibility Criteria".