DiagBench: Evaluating Diagnostic Revision in Large Language Models with Longitudinal Inpatient Records

Huawei Feng, Dongsheng Shi, Linlin Wang


Abstract
Reliable clinical decision support requires tracking evidence over a hospital stay and revising a disease diagnosis when new findings challenge the initial assessment. Strong performance on medical question answering does not establish that large language models (LLMs) can make these longitudinal decisions. We introduce DiagBench, a benchmark of 2,865 Chinese inpatient admissions that evaluates diagnostic revision as clinical evidence accumulates. It pairs admission-only prediction with staged evidence disclosure, distinguishing an unchanged diagnosis, refinement of an existing hypothesis, and replacement by a different diagnosis. Development and test cases have human-annotated reference labels. The best LLM configuration in the main evaluation achieves only 52.6% macro recall; 80.3-87.7% of errors across five DeepSeek-Chat (DeepSeek-V3.2, non-thinking mode) prompting strategies occur between adjacent revision categories. Strategies that improve final-diagnosis prediction do not consistently improve revision decisions. We further use DiagAgent to trace diagnoses and evidence across rounds, revealing failures to replace an initial hypothesis despite recognizing contradictory findings. On DeepSeek-Chat, a single agent with the same state outperforms the full system on macro recall.
Anthology ID:
2026.findings-aacl.193
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
3821–3832
Language:
URL:
https://aclanthology.org/2026.findings-aacl.193/
DOI:
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Cite (ACL):
Huawei Feng, Dongsheng Shi, and Linlin Wang. 2026. DiagBench: Evaluating Diagnostic Revision in Large Language Models with Longitudinal Inpatient Records. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 3821–3832, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
DiagBench: Evaluating Diagnostic Revision in Large Language Models with Longitudinal Inpatient Records (Feng et al., Findings 2026)
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https://aclanthology.org/2026.findings-aacl.193.pdf