Diagnostic Accuracy of Immature Granulocyte Count for Early Sepsis Detection: A Comparative Evaluation With...

Sepsis is a life-threatening condition characterized by a dysregulated host response to infection, resulting in organ dysfunction and high mortality rates among critically ill patients. Early recognition is essential for prompt therapeutic intervention; however, nonspecific clinical presentation often delays diagnosis. Conventional biomarkers, such as C-reactive protein (CRP) and procalcitonin (PCT), are frequently used, but their diagnostic performance varies. Immature granulocyte (IG) parameters obtained from routine hematological analyses have recently gained attention as potential early indicators of sepsis. This study aimed to evaluate the diagnostic accuracy of immature granulocyte count (IG#) and immature granulocyte percentage (IG%) for early sepsis detection and compare their performance with that of CRP and PCT in critically ill patients.

This retrospective observational study included 178 critically ill patients admitted to the intensive care unit of a single institution. Laboratory investigations performed within 24 hours of admission included complete blood count with IG parameters, CRP, PCT, lactate, and other biochemical markers. Patients were monitored for the development of sepsis and subsequently categorized into sepsis and non-sepsis groups. The diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis.

Of the 178 patients, 72 developed sepsis during the observation period. Patients with sepsis demonstrated significantly elevated IG#, IG%, PCT, CRP, lactate, white blood cell count, neutrophil percentage, serum creatinine, and bilirubin levels compared with patients without sepsis. ROC curve analysis revealed good diagnostic performance for IG%, followed by IG# and PCT, whereas CRP demonstrated a comparatively lower discriminatory ability. The combination of IG% and PCT achieved the best overall diagnostic performance, indicating improved accuracy in identifying patients at risk of developing sepsis. Elevated immature granulocyte parameters were strongly associated with sepsis and reflected early activation of the bone marrow response to infection.

Immature granulocyte parameters, particularly IG%, are reliable and readily available biomarkers for early sepsis detection. Their diagnostic performance is comparable to that of established markers and may be enhanced when combined with procalcitonin. Routine assessment of immature granulocytes may facilitate the early recognition of sepsis and support timely clinical decision-making in critically ill patients.