Neutrophil CD64 Index: A Novel Biomarker for Risk Stratification in Acute Pancreatitis

Min Shao ¹ Ling Wu ¹ Xiangping Huang ¹ Qianhui Ouyang ¹ Ya Peng ² Sixiang Liu ³ Xu Xu ¹ Qi Yi ³ Yi Liu ⁴ Guoguang Li ⁴ Ning Ding ⁵ Jia Wang ^6* Chaochao Tan ^7,8* Ying Huang ^3*

• ¹ Department of Clinical Laboratory, Hunan Provincial People’s Hospital, Changsha, Hunan Province, China
• ² Department of Gastroenterology, Hunan Provincial People's Hospital, Changsha, Hunan Province, China
• ³ Department of Emergency, Hunan Provincial People's Hospital, Changsha, Anhui Province, China
• ⁴ Department of Hepatobiliary Surgery, Hunan Provincial People's Hospital, Changsha, Hunan Province, China
• ⁵ Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan Province, China
• ⁶ Hunan Provincial Key Laboratory of Emergency and Critical Care Metabolomics, Changsha, Anhui Province, China
• ⁷ Hunan Provincial People's Hospital, Changsha, China
• ⁸ Hunan Provincial Elderly Hospital, Changsha, Hunan Province, China

Objective: Effective early diagnosis and timely intervention in acute pancreatitis (AP) are essential for improving patient outcomes. This study aims to evaluate the clinical utility of the neutrophil CD64 index (nCD64) in stratifying patients with SAP and assessing mortality risk.Methods: A total of 302 AP patients were enrolled and divided into a training cohort (n = 226) and a validation cohort (n = 76). Venous blood samples were collected within 24 hours of admission, and the nCD64 index was measured via flow cytometry. Other clinical parameters, including C-reactive protein (CRP) and procalcitonin (PCT), were also recorded. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic value of the nCD64 index and its capacity to predict mortality risk.Results: ROC curve analysis identified a cutoff value of 1.45 for the nCD64 index. Patients with nCD64 > 1.45 had significantly higher risks of complications, including systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), multiple organ failure (MOF), and death. Over 65% of patients with acute pancreatitis (AP) can be effectively risk-stratified at a low cost, and it has been demonstrated that AP patients with an nCD64 value ≤ 1.45 have an extremely low mortality rate (no mortality in present training and validation cohort). Kaplan-Meier survival analysis revealed a significant survival difference between high-risk (nCD64 > 1.45) and low-risk groups (p < 0.001).The nCD64 index is an effective tool for early identification of SAP patients, allowing for the classification of over 65% of cases as low-risk for mortality.