MedUPS 用强化学习教模型在罕见病例中预测下一步决策，三个开源模型准确率都提升了，数据集和代码已开源。
MedUPS 是一个针对罕见病例诊断决策的对齐框架，配套数据集 MedUPSQA 包含 21,874 个临床决策点，来自 5,535 份真实病例报告。该框架将病例文本按时间顺序切分成累积片段，用 GRPO 强化学习训练模型预测下一步行动，并以 LLM-as-a-Judge 作为奖励。在三个基座模型上，中间步骤对齐将下一步预测准确率从 55.2 提升至 66.7（Qwen3.6-27B）、从 47.2 提升至 57.8（Qwen3.5-9B）、从 37.8 提升至 44.4（HuatuoGPT-3-8B）。MedUPSQA 数据集、代码和对齐后的模型权重已发布。
MedUPS: Towards Diagnostic Assistance in Uncommon Medical Cases with Large Language Models
Uncommon and off-guideline cases are difficult for clinical decision support, because physicians must make a series of management decisions under diagnostic uncertainty and rarely see the full case at once. Most large language model (LLM) benchmarks for medicine score only the final diagnosis, yet much of clinical care turns on the next appropriate action: the next test to order, the imaging study to obtain, the specialist to involve, or the differential to pursue. We introduce MedUPSQA, a dataset of 21,874 mid-stream clinical decision points built from 5,535 real case reports, and MedUPS, an alignment framework that supervises models on these intermediate decisions as they unfold along a patient's trajectory. We segment free-text case presentations into chronologically ordered, accumulating clinical chunks and align models to predict the next step with reinforcement learning (GRPO), using an external LLM-as-a-Judge reward. This objective mirrors how clinicians actually meet patients, reasoning forward from accumulating evidence toward the next decision, rather than committing to a final label. Across three backbones, mid-stream alignment raises next-step accuracy from 55.2 to 66.7 for Qwen3.6-27B, from 47.2 to 57.8 for Qwen3.5-9B, and from 37.8 to 44.4 for HuatuoGPT-3-8B, with 95% CI. In several model scales we test the objective improves accuracy more than scale, with smaller models surpassing larger, frontier models we evaluate. We further train supervised fine-tuning (SFT) baselines on the mid-stream task, SFT improves all backbones above base, indicating the target framwork carries signal independently of the optimizer. We release the dataset, code, and aligned checkpoints.