Evaluation of Neutrophil cluster of differentiation 64 in adult sepsis as a novel diagnostic biomarker

Background: Sepsis stands as a leading cause of mortality among critically ill patients in intensive care units (ICUs). Bacterial infections, including sepsis, upregulate Neutrophilic cluster of differentiation 64 (nCD64) expression on activated polymorphonuclear leukocytes (PMNs). Prompt diagnosis of sepsis is crucial for initiating timely and targeted treatment. Consequently, a rapid laboratory test with high specificity for sepsis in adults would significantly aid therapeutic decision-making and help reduce the overuse of antibiotics. Methods: This study enrolled 40 sepsis patients diagnosed according to the Sepsis-3 definition. For biomarker evaluation, 2 mL blood samples were collected from each patient in both ethylenediaminetetraacetic acid (EDTA) and plain vials. In addition, nCD64 was analyzed using flow cytometry, high-sensitivity C-reactive protein (hs-CRP) via nephelometry, and procalcitonin (PCT) using chemiluminescence. Results: For sepsis prediction, nCD64 demonstrated a positive predictive value (PPV) of 92.68% and a negative predictive value (NPV) of 94.87%. A receiver operating characteristic (ROC) curve was generated to assess the diagnostic accuracy of nCD64 (≥ 1.8), hS-CRP (≥ 3 mg/L), and PCT (≥ 0.4 ng/mL). The area under the curve (AUC) for nCD64 was highest at 0.938 (95% confidence interval [CI] = 0.876-0.999), followed by hS-CRP at 0.888 (95% CI = 0.807-0.968) and PCT at 0.850 (95% CI = 0.759-0.941). Conclusion: These findings strongly suggest that nCD64 determination is a valuable diagnostic tool for identifying infections in patients with septic syndrome. Its performance appears to be superior to that of hs-CRP and PCT.