SemAnTICA Lab at MediQA-SYNUR 2026: Route, Extract and Verify – An LLM-gated Ensemble for Parsing Nurse Dictations

Sy Hwang, Katherine S. Pitcher, Sue Hyon Kim, Yoonjae Lee, Hayoung K. Donelly, Harsh Bandhey, Andrew J. King, Karen O’Connor, Ryan J. Urbanowicz, Danielle L. Mowery


Abstract
We describe the Semantic Analysis of Text to Inform Clinical Action (SemAnTICA) Lab’s system for the MediQA-SYNUR 2026 shared task on extracting structured clinical observations from nurse dictation transcripts. The task requires mapping observations from disfluent conversational text to a large, fixed ontology and producing strictly normalized outputs, where small amounts of concept over-selection severely degrade micro-F1 score. Our approach evolved from a full-schema in-context baseline to a pipeline that explicitly separates concept selection from value extraction. We first preprocess transcripts, then generate transcript-specific concept candidates using hybrid sparse–dense retrieval. The candidates are then pruned with an evidence-based filter. For extraction, we adopt a system-level mixture-of-experts design with an online LLM router that selects a subset of domain-specialized experts per transcript. Each expert operates over a constrained schema partition to reduce spurious predictions. We enhance robustness with agreement-gated ensembling and targeted adjudication for ambiguous cases. Finally, we intersect complementary high-recall and high-precision runs to produce the best submission. Our system ranked first on the official test leaderboard with F1 = 0.814, P = 0.826, R = 0.801.
Anthology ID:
2026.clinicalnlp-1.4
Volume:
Proceedings of the 8th Workshop on Clinical Natural Language Processing (Clinical NLP) @ LREC 2026
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Asma Ben Abacha, Steven Bethard, Danielle Bitterman, Tristan Naumann, Kirk Roberts
Venues:
ClinicalNLP | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
27–37
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-clinicalnlp-04
DOI:
10.63317/3cfpmqqpmdq5
Bibkey:
Cite (ACL):
Sy Hwang, Katherine S. Pitcher, Sue Hyon Kim, Yoonjae Lee, Hayoung K. Donelly, Harsh Bandhey, Andrew J. King, Karen O’Connor, Ryan J. Urbanowicz, and Danielle L. Mowery. 2026. SemAnTICA Lab at MediQA-SYNUR 2026: Route, Extract and Verify – An LLM-gated Ensemble for Parsing Nurse Dictations. In Proceedings of the 8th Workshop on Clinical Natural Language Processing (Clinical NLP) @ LREC 2026, pages 27–37, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
SemAnTICA Lab at MediQA-SYNUR 2026: Route, Extract and Verify – An LLM-gated Ensemble for Parsing Nurse Dictations (Hwang et al., ClinicalNLP 2026)
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