Abstract

Objectives: The aim of this study was to evaluate the diagnostic performance of monocyte-based biomarkers in pediatric acute appendicitis (AA) and to investigate their potential role in the differential diagnosis of nonspecific abdominal pain (NAP).

Patients and Methods: This retrospective observational study included consecutive pediatric patients who presented to the emergency department with abdominal pain between June 2021 and December 2024. Patients were categorized into two groups: histopathologically confirmed AA and NAP with a normal appendix on abdominal computed tomography. Demographic characteristics and laboratory parameters, including white blood cell count (WBC), neutrophil percentage (NP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte (MO) count, monocyte-to-lymphocyte ratio (MLR), lymphocyteto-monocyte ratio (LMR), and monocyte-to-MPV ratio (MMR), were analyzed. Diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis.

Results: A total of 550 patients were included in the study, consisting of 200 patients in the AA group (121 male, 79 female; mean age: 11.9 ± 3.5 years; range, 3.5 to 18 years) and 350 in the NAP group (180 male, 170 female; mean age: 11.3 ± 3.8 years; range, 4 to 18 years). Patients with AA had significantly higher levels of WBC, NP, NLR, PLR, MO count, and MLR, whereas lymphocyte count, LMR, and MMR were significantly lower (p < 0.05). The ROC analysis demonstrated the highest diagnostic accuracy for LMR (area under the curve, AUC = 0.848) and MLR (AUC = 0.848), followed by NLR (AUC = 0.824). In multivariate analysis, LMR remained independently associated with AA. An LMR cut-off value of 2.98 yielded 75% sensitivity and 75.2% specificity. Higher LMR values were particularly useful for ruling out appendicitis.

Conclusion: Monocyte-based ratios, particularly LMR and MLR, demonstrated good diagnostic performance in differentiating pediatric AA from NAP in a clinically relevant cohort. Although not disease-specific, these inexpensive and readily available biomarkers may provide useful adjunctive information in children with equivocal presentations. In particular, LMR may support ruling out appendicitis and aid clinical decision-making, pending prospective validation.

Citation: Huseynov M, Kabaklioglu M. Diagnostic value of monocyte-based ratios for pediatric acute appendicitis. Turkish J Ped Surg 2026;40(3):115-122. doi: 10.62114/JTAPS.2026.272.