EviDx: Evidence-Aware Active Diagnosis with Scaffolded LLM Agents

Lihang Zeng, Shaoting Zhang, Xiaofan Zhang


Abstract
Clinical diagnosis is an active evidence-seeking process in which clinicians acquire evidence, update competing hypotheses, and decide when the available evidence is sufficient for diagnosis. Yet many medical diagnosis systems built around large language models (LLMs) still formulate diagnosis as static case-to-answer prediction, with limited support for evidence acquisition. Agentic LLMs offer a dynamic alternative through tool use and intermediate diagnostic trajectories, but existing systems often under-specify how patient evidence should be exposed, scaffolded, and controlled at runtime. We introduce EviDx, an evidence-aware active diagnosis framework that pairs patient-specific diagnostic environments with a clinical diagnostic scaffold and an observer-guided runtime harness. In EviDx, ℰ-Synthesis constructs interactive environments from raw clinical cases; the scaffold organizes role-specialized agents, evidence tools, and evolving evidence states; and the harness regulates diagnostic termination by tracking uncertainty and evidence coverage. A 3-level evaluation pyramid assesses execution robustness, reasoning dynamics, and diagnostic outcomes. Experiments show that EviDx improves diagnostic performance and process stability while revealing model-dependent capability boundaries.
Anthology ID:
2026.findings-emnlp.1557
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
33154–33179
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1557/
DOI:
10.18653/2026.findings-emnlp.1557
Bibkey:
Cite (ACL):
Lihang Zeng, Shaoting Zhang, and Xiaofan Zhang. 2026. EviDx: Evidence-Aware Active Diagnosis with Scaffolded LLM Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 33154–33179, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
EviDx: Evidence-Aware Active Diagnosis with Scaffolded LLM Agents (Zeng et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1557.pdf