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GPT-RagAD: Two-layer Retrieval-Augmented Multilingual Diagnosis System
Proceedings of the Fifth Machine Learning for Health Symposium, PMLR 297:152-166, 2026.
Abstract
We introduce GPT-RagAD, a multilingual, zero-shot automated diagnosis system that achieves high accuracy without relying on real patient data. GPT-RagAD adopts a two-layer Retrieval-Augmented Generation (RAG) architecture: a knowledge graph-based retriever selects disease candidates from 1,058 conditions, and an LLM-based re-ranker applies prompt-based reasoning to refine predictions. Unlike traditional diagnostic models that require supervised training and large clinical datasets, GPT-RagAD is privacy-preserving, scalable, and language-agnostic. Extensive evaluations on three multilingual datasets (Chinese and English) show that GPT-RagAD achieves 40.6% Hit@1 and 56.7% NDCG@10 on the Symptom2Disease benchmark—substantially outperforming embedding-based and direct LLM baselines. Ablation and sensitivity analyses further validate its robustness. GPT-RagAD presents a practical, lightweight solution for clinical triage and pre-diagnosis support.