Prognostic Performance of the Admission C-Reactive Protein to Lymphocyte Ratio in Acute Pancreatitis

Abstract: Background: Early risk stratification in acute pancreatitis (AP) is important, but many prognostic scores are complex or require serial measurements. We evaluated the admission C-reactive protein-to-lymphocyte ratio (CLR) as a predictor of moderately severe/severe AP. Objective: To assess the diagnostic performance of admission CLR for predicting moderately severe or severe AP (MSAP/SAP) and to derive an optimal admission cut-off for early risk stratification. Materials and Methods: The Prospective, exploratory diagnostic accuracy study was conducted during January 1st 2024 to 30th June 2025. It was done in collaboration with the Department of Medicine and the Department of Pathology, Quaid-e-Azam Medical College and Bahawal Victoria Hospital, Bahawalpur bearing Ethical approval no. (IRB QAMC 1585, Dated 15 December 2023). Out of 72 AP patients screened, 12 were excluded (including missing admission CRP or absolute lymphocyte count), leaving 60 for complete-case analysis (40 mild AP, 20 MSAP/SAP). Labs were obtained within 24 hours. Discrimination was assessed by ROC analysis and association with MSAP/SAP used Firth-penalized logistic regression limited to pre-specified predictors (CLR per 10 units and age) to reduce overfitting. Result: Patients who developed MSAP/SAP had higher admission CRP and CLR values, with no significant differences in age or sex between groups. Median CLR increased from 33.6 (IQR 23.7–52.4) in mild AP to 236.5 (IQR 163.2–288.1) in MSAP/SAP (p<0.001). Each 10-unit CLR increase was independently associated with MSAP/SAP (adjusted OR 1.63, 95% CI 1.22–2.37; p=0.001). CLR showed good discrimination (AUC 0.818, 95% CI 0.693–0.942). A Youden-derived cut-off of 67.7 yielded 85.0% sensitivity and 72.5% specificity. Length of stay was longer in MSAP/SAP (10.1±1.9 vs 5.8±2.4 days; p<0.001). Conclusion: Admission CLR ≥67.7 was associated with MSAP/SAP and may aid risk assessment. Because CRP alone showed higher discrimination, CLR should be viewed as an adjunct, not a substitute for established CRP strategies (including 48-hour CRP). Larger multicenter studies should validate the threshold and assess whether serial CLR adds prognostic value. Keywords: Acute pancreatitis, C reactive protein, Lymphocyte count, Severity prediction, Biomarker.