CLR (CRP to Lymphocytes) Score for Differentiating Simple and Complicated Appendicitis in Pediatric Patients

Acute appendicitis, a frequent pediatric surgical emergency, requires distinguishing simple from complicated cases for treatment decisions. Current tools, such as clinical scores and ultrasound, are sometimes ineffective. This study evaluates the biomarkers: neutrophils to lymphocytes ratio (NLR), monocytes to lymphocytes ratio (MLR), platelet-to-lymphocyte ratio (PLR), neutrophils to monocytes ratio (NMR), neutrophils to platelet ratio (NPR), pan-immune-inflammation value (PIV) ratio, and C-Reactive Protein (CRP) to lymphocytes ratio (CLR) for differentiation between simple and complicated appendicitis.

A retrospective study of 878 pediatric patients (<18 years) who underwent appendectomy (2018–2024) at a tertiary medical center, with appendicitis classified as simple (SA, n = 696) or complicated (CA, n = 182) using intraoperative findings. Biomarkers were calculated from preoperative blood counts and CRP. Diagnostic accuracy was assessed using Mann–Whitney U tests, ROC curves, and logarithmic regression.