In Reply We thank Freund et al for their interest in our article¹ and for their contribution to the discussion. The 4-Level Pulmonary Embolism Clinical Probability Score (4PEPS) strategy leads to an overall very low false-negative rate, the upper limit of the 95% CI being below the threshold recommended by the Scientific and Standardization Committee of the International Society of Thrombosis and Hemostasis. However, they question its safety in the specific subgroup of patients with a very low clinical pretest probability (CPP), ie, those with a 4PEPS less than 0. Indeed, in the validation cohorts, the upper limit of the false-negative rate was higher than 2% for this subgroup of patients. We agree that, ideally, a very low failure rate should be confirmed in each subgroup for whom the rule-out criteria differed. However, we do not consider this subgroup analysis to invalidate our promising results.

在回复中我们感谢 Freund 等人对我们的文章¹的兴趣并感谢他们对讨论的贡献。4 级肺栓塞临床概率评分 (4PEPS) 策略导致总体假阴性率非常低，95% CI 的上限低于国际血栓形成学会科学和标准化委员会推荐的阈值，并且止血。然而，他们质疑其在临床前测概率 (CPP) 极低的特定患者亚组中的安全性，即 4PEPS 小于 0 的患者。 事实上，在验证队列中，假阴性率的上限是该亚组患者高于 2%。我们同意，理想情况下，应该在排除标准不同的每个亚组中确认非常低的失败率。然而，我们不认为这个亚组分析会使我们有希望的结果无效。