Inflammatory Biomarkers in Sepsis Diagnosis and Prognosis

Sepsis arises when a dysregulated host response to infection triggers widespread inflammation, leading to organ dysfunction and significant mortality. Inflammatory biomarkers serve as measurable indicators of this host response, offering clinicians tools for early diagnosis, risk stratification and monitoring of therapeutic response. Traditional markers such as C-reactive protein and procalcitonin have been widely adopted, reflecting acute-phase hepatic synthesis and microbial toxin-induced cytokine release respectively. More recently, haematological parameters derived from routine complete blood counts have gained traction. These include monocyte distribution width, delta neutrophil index and immature granulocyte counts, which mirror shifts in myeloid cell morphology and bone-marrow output under inflammatory stress. Advances in immunoassays and machine-learning have enabled rapid, point-of-care analysis, combining multiple biomarkers to improve sensitivity and specificity. Prognostically, dynamic changes in these markers correlate with clinical outcomes, guiding the intensity of monitoring and critical interventions. Despite promising findings, the clinical integration of novel biomarkers demands validation across diverse populations and standardisation of assay thresholds to ensure reproducible decision support in sepsis management.

Research from Nature Portfolio

Recent studies have demonstrated that monocyte distribution width offers robust diagnostic performance in patients presenting to the emergency department with suspected infection and sepsis. In a multicentre cohort exceeding 1,900 adult admissions, monocyte distribution width alone achieved an area under the receiver operating characteristic curve of 0.84 for infection and 0.83 for sepsis, comparable to procalcitonin and C-reactive protein. Optimal cut-off values distinguished infection at a threshold of 21 (sensitivity 73%, specificity 82%) and sepsis at 22 (sensitivity 79%, specificity 83%). When combined with organ-dysfunction markers such as creatinine, bilirubin and platelet count, diagnostic accuracy rose to an AUC of 0.96, with sensitivity of 94% and specificity of 88%. These findings underscore the value of integrating cellular biomarkers with physiological indices to enhance early sepsis detection.

Inflammatory Biomarkers in Sepsis Diagnosis and Prognosis publication trend

The graph below shows the total number of articles in inflammatory biomarkers in sepsis diagnosis and prognosis across all publications each year (not limited to Nature Index journals).

Technical terms

Monocyte distribution width (MDW): A measure of variability in monocyte size reflecting activation and morphological changes during infection.

Procalcitonin (PCT): A peptide precursor of calcitonin that rises in bacterial infection, used for sepsis diagnosis and antibiotic guidance.

C-reactive protein (CRP): An acute-phase protein synthesised by the liver in response to interleukin-6, indicative of systemic inflammation.

Delta neutrophil index (DNI): The proportion of circulating immature granulocytes, calculated from automated blood analysers as an indicator of myeloid response.

Complete blood count (CBC): A routine panel quantifying blood cell populations and indices, forming the basis for haematological biomarkers in sepsis.

References

1. Monocyte distribution width (MDW) as a reliable diagnostic biomarker for sepsis in patients with HIV. Emerging Microbes & Infections (2025).
2. Complete Blood Count and Monocyte Distribution Width–Based Machine Learning Algorithms for Sepsis Detection: Multicentric Development and External Validation Study. Journal of Medical Internet Research (2025).
3. Understanding the value of monocyte distribution width (MDW) in acutely ill medical patients presenting to the emergency department: a prospective single center evaluation. Scientific Reports (2024).