背景 细胞学不确定的甲状腺结节（ITNs）的分子测试经常只提供有关临床评估和超声恶性风险（USMR）分层的不完整数据。本研究旨在临床验证一种新型分子测试的诊断准确性，评估其他临床因素的术前恶性风险增量，并测量引入分子测试对人群水平的影响。 方法 在引入反应性分子测试后，首615例连续ITNs患者在一个集中的医疗保健系统中前瞻性收集了全面的临床数据。临床数据包括患者病史、结节发现方法、临床评估、USMR、细胞学、分子测试以及手术或随访，并包括外科医生对手术决策的笔记。计算了分子测试的准确性和引入分子测试的影响。开发了多变量回归模型以确定哪些临床因素对ITNs具有最大的诊断意义。 结果 使用标准液体细胞学细针穿刺（FNA）剩余材料，一种经济实惠的本地开发的分子测试在ITNs中实现了76-91%（95% CI 66-95%）的阴性预测值（NPV）和46-65%（95% CI 37-75%）的阳性预测值（PPV）。敏感性在ATA中度疑似超声类别中最高（80%；95% CI 63-92%），在ATA高度疑似超声类别中最低（46%；95% CI 19-75%）。引入分子检测后，诊断产出增加了14%（p=0.2442），重复FNA减少了24%（p=0.05）。突变是76%的患者手术的主要原因。高风险突变与手术等待时间减少了58%（p=0.0001）。26%的负分子测试结果的患者进行了手术。多变量回归强调分子测试和USMR与恶性相关。 结论 分子测试可以改善术前风险分层，但需要进一步分层中风险突变。将临床因素（尤其是USMR）与分子测试结合使用可能增加恶性检测的敏感性。在低切除率的情况下，引入分子测试也带来一些临床益处，并直接影响外科手术决策。本研究阐明了地方诊断途径对确保最佳结果的分子测试的适当整合使用的重要性。

Background Molecular testing for cytologically indeterminate thyroid nodules (ITNs) is often reported with incomplete data on clinical assessment and ultrasound malignancy risk (USMR) stratification. This study aimed to clinically validate the diagnostic accuracy of a novel molecular test, assess the incremental preoperative malignancy risk of other clinical factors, and measure the impacts of introducing molecular testing at the population level. Methods Comprehensive clinical data were collected prospectively for the first 615 consecutive patients with ITNs in a centralized healthcare system following implementation of a reflexive molecular test. Clinical data includes patient history, method of nodule discovery, clinical assessment, USMR, cytology, molecular testing, and surgery or follow-up along with surgeon notes on surgical decision-making. Accuracy of molecular testing and the impact of the introduction of molecular testing were calculated. A multivariable regression model was developed to identify which clinical factors have the most diagnostic significance for ITNs. Results A locally developed, low-cost molecular test achieved an NPV of 76-91% (95% CI 66-95%) and a PPV of 46-65% (95% CI 37-75%) in ITNs using only residual material from standard liquid cytology fine needle aspiration (FNA). Sensitivity was highest (80%; 95% CI 63-92%) in the ATA intermediate suspicion ultrasound category, and lowest (46%; 95% CI 19-75%) in the ATA high suspicion ultrasound category. Following implementation of molecular testing, diagnostic yield increased 14% (p=0.2442) and repeat FNAs decreased by 24% (p=0.05). Mutation was the primary reason for surgery in 76% of resected, mutation positive patients. High risk mutations were associated with a 58% (p=0.0001) shorter wait for surgery. 26% of patients with a negative molecular test result underwent surgery. Multivariable regression highlighted molecular testing and USMR as significantly associated with malignancy. Conclusions Molecular testing improves preoperative risk stratification but requires further stratification for intermediate risk mutations. Incorporation of clinical factors (especially USMR) with molecular testing may increase sensitivity for detection of malignancy. Introduction of molecular testing offers some clinical benefits even in a low resection rate setting, and directly influences surgical decision-making. This study illustrates the importance of the local diagnostic pathway in ensuring appropriate integrated use of molecular testing for best outcomes.