Diagnostic Value of Hematological and Biochemical Markers in Pediatric Appendicitis: A ROC-Based Retrospective Evaluation

Abs tractAim: Acute appendicitis is the most common surgical emergency in children; however, its diagnosis often remains challenging due to non-specific clinical features and overlapping laboratory results with other abdominal conditions.We aimed to evaluate the diagnostic accuracy of routine hematological and biochemical markers as accessible and reliable tools to support early and precise diagnosis of pediatric appendicitis.Methods: This retrospective study included pediatric patients aged 0-18 years who were evaluated in the pediatric surgery department between April and June 2025.Patients were divided into three groups based on clinical, radiological, and histopathological findings: histopathologically confirmed acute appendicitis (n=63), right lower quadrant pain with appendicitis excluded (n=71), and healthy controls (n=74).Laboratory parameters analyzed at admission included white blood cell, neutrophils, lymphocytes, neutrophil-tolymphocyte ratio (NLR), platelet-to-lymphocyte ratio, mean corpuscular volume, red cell distribution width, mean platelet volume (MPV), platelet count, C-reactive protein (CRP), albumin, total bilirubin, direct bilirubin, sodium, and phosphorus.Diagnostic performance was evaluated using receiver operating characteristic curve analysis and multivariable logistic regression.Results: Multivariable logistic regression identified seven independent predictors of acute appendicitis: direct bilirubin, albumin, CRP, MPV, sodium, NLR, and total bilirubin.Among these, direct bilirubin [odds ratio (OR)=8.34,p=0.0006) and albumin (OR=0.42,p=0.0021) were the strongest independent predictors, while CRP, MPV, and sodium also remained significant (p<0.05).Although NLR and total bilirubin were included in the model, their associations did not reach statistical significance.The final seven-parameter PediACS model demonstrated excellent discriminative performance (area under the curve=0.903;95% confidence interval: 0.86-0.94).Using the optimal cut-off value (0.214) determined by the Youden Index, the model achieved 85.7% sensitivity, 89.7% specificity, and an overall diagnostic accuracy of 87.9%. Conclusion:The PediACS model, derived from routine laboratory parameters, reliably distinguishes acute appendicitis from non-specific abdominal pain in children.It represents a practical, reproducible, and cost-effective diagnostic tool, particularly beneficial when imaging resources are limited or radiological results are inconclusive.