Understanding the Limits of Agentic ICD Coding

Eng Chong Yock, Yushi Cao, Yiming Chen, Kezhi Mao, Hongchao Jiang


Abstract
ICD-10 codes are alphanumeric codes used in the US to classify diagnoses and injuries for medical billing and epidemiological reporting. Standard ICD-10 benchmarks report aggregate metrics that obscure performance on complex coding scenarios. We evaluate neural, workflow, and agentic systems on a rarity-stratified set of MIMIC-IV discharge summaries and identify two orthogonal failure modes. Neural classifiers exhibit a 0.43 micro-F1 gap between rare and common codes. Workflow systems handle rare codes well but score near zero on injury and external cause codes that require multi-step guideline following. A tool-augmented agentic configuration with structured access to official ICD-10 reference materials recovers up to 0.32 micro-F1 on this subset. No single system dominates across all conditions.
Anthology ID:
2026.emnlp-main.1583
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
36028–36037
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1583/
DOI:
Bibkey:
Cite (ACL):
Eng Chong Yock, Yushi Cao, Yiming Chen, Kezhi Mao, and Hongchao Jiang. 2026. Understanding the Limits of Agentic ICD Coding. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 36028–36037, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Understanding the Limits of Agentic ICD Coding (Yock et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1583.pdf