Dharma: A novel, clinically grounded machine learning framework for pediatric appendicitis-Diagnosis, severity assessment and evidence-based clinical decision support.

Acute appendicitis is a common but diagnostically challenging surgical emergency in children. Existing linear scoring systems lack sufficient accuracy for standalone use, while advanced imaging is constrained by risks of sedation, contrast, and radiation. Furthermore, no available tools provide prognostic guidance. We introduce Dharma, a machine learning framework consisting of a clinically grounded imputer and two random forest classifiers for diagnosis and severity assessment. Designed for real-world bedside use, Dharma is open-sourced and accessible through a web application. Dharma achieved excellent diagnostic performance, with an AUC-ROC of 0.98 [0.97-0.99] and accuracy of 93% [91-95]. For prognostic classification, it identified complicated appendicitis with high sensitivity (96% [93-99]) and negative predictive value (97% [94-99]). Even in cases without appendix visualization-a frequent limitation in resource-constrained settings-Dharma maintained strong performance (AUC-ROC 0.96 [0.93-0.99]), with specificity of 97% [93-100] and PPV of 93% [84-100] at a 44% threshold, and sensitivity of 92% [84-98] with NPV of 95% [91-99] at a 25% threshold. These threshold-dependent trade-offs enable Dharma to support both ruling in and ruling out appendicitis within diverse clinical workflows. Beyond pediatric appendicitis, Dharma's open-source framework and clinically grounded design also provide a generalizable foundation for developing equitable and practical decision-support systems in healthcare.