SAA1 as a Potential Early Diagnostic Biomarker for Sepsis Through Integrated Proteomics and Metabolomics

ABSTRACT Sepsis is characterised by fatal organ dysfunction resulting from a dysfunctional host response to infection, imposing a substantial economic burden on families and society. Therefore, identifying biomarkers for early sepsis diagnosis and improving patient prognosis are critical. This study recruited 59 sepsis patients and 35 healthy volunteers from the Department of Critical Care Medicine at Harbin Medical University Affiliated First Hospital between March and December 2021. Through a combination of non‐targeted and targeted proteomics and metabolomics sequencing, along with various analytical methods, we initially identified and validated serum amyloid A1 (SAA1) as a diagnostic biomarker for sepsis. Our study found that SAA1 was significantly elevated in the sepsis group, demonstrating its diagnostic value for sepsis ( AUC : 0.95, 95% CI : 0.88–1). Additionally, a positive correlation was observed between SAA1 and disease severity, as indicated by the Sequential Organ Failure Assessment ( SOFA ) score ( R = 0.51, p = 0.004) and Acute Physiology and Chronic Health Evaluation II ( APACHE II ) score ( R = 0.52, p = 0.003). This study suggests that SAA1 is a potentially effective and reliable marker for diagnosing sepsis and predicting its severity.