Temporal trends of a cellular host response test for sepsis and a comparison with selected biomarkers of inflammation and infection.

Sepsis, a condition characterized by immune dysregulation, is the leading cause of in-hospital mortality and requires rapid treatment. Assessing immune dysregulation has been challenging. The IntelliSep Index (ISI), a novel biomarker which leverages microfluidic deformability cytometry to assess immune activation, has been evaluated as a test for Emergency Department use but it is unclear how the signal evolves as patient condition evolves. In a 47-patient cohort with hospital stays ≤ 14 days, ISI provided a good indicator of disease progression by blinded physician review. ISI trends correlated with clinical improvement over time. During the first 12 h following presentation, ISI was unaffected by antibiotic treatment initiated in the emergency department (ED). After this period however, ISI values declined, reflecting the patient's response to treatment, with Band 3 patients showing a 20% decline within the first two days of admission. ISI trends preceded Sequential Organ Failure Assessment (SOFA) score changes by two days. ISI also provided more stable and timely disease state assessments compared to traditional biomarkers (PCT, CRP, IL-6, and neutrophil elastase). Larger studies are needed to validate these findings and assess ISI's clinical utility as a prognosticator of sepsis progression and treatment response.