BACKGROUND Retrospective analyses suggest that pulmonary embolism is ruled out by a d-dimer level of less than 1000 ng per milliliter in patients with a low clinical pretest probability (C-PTP) and by a d-dimer level of less than 500 ng per milliliter in patients with a moderate C-PTP. METHODS We performed a prospective study in which pulmonary embolism was considered to be ruled out without further testing in outpatients with a low C-PTP and a d-dimer level of less than 1000 ng per milliliter or with a moderate C-PTP and a d-dimer level of less than 500 ng per milliliter. All other patients underwent chest imaging (usually computed tomographic pulmonary angiography). If pulmonary embolism was not diagnosed, patients did not receive anticoagulant therapy. All patients were followed for 3 months to detect venous thromboembolism. RESULTS A total of 2017 patients were enrolled and evaluated, of whom 7.4% had pulmonary embolism on initial diagnostic testing. Of the 1325 patients who had a low C-PTP (1285 patients) or moderate C-PTP (40 patients) and a negative d-dimer test (i.e., <1000 or <500 ng per milliliter, respectively), none had venous thromboembolism during follow-up (95% confidence interval [CI], 0.00 to 0.29%). These included 315 patients who had a low C-PTP and a d-dimer level of 500 to 999 ng per milliliter (95% CI, 0.00 to 1.20%). Of all 1863 patients who did not receive a diagnosis of pulmonary embolism initially and did not receive anticoagulant therapy, 1 patient (0.05%; 95% CI, 0.01 to 0.30) had venous thromboembolism. Our diagnostic strategy resulted in the use of chest imaging in 34.3% of patients, whereas a strategy in which pulmonary embolism is considered to be ruled out with a low C-PTP and a d-dimer level of less than 500 ng per milliliter would result in the use of chest imaging in 51.9% (difference, -17.6 percentage points; 95% CI, -19.2 to -15.9). CONCLUSIONS A combination of a low C-PTP and a d-dimer level of less than 1000 ng per milliliter identified a group of patients at low risk for pulmonary embolism during follow-up. (Funded by the Canadian Institutes of Health Research and others; PEGeD ClinicalTrials.gov number, NCT02483442.).

中文翻译：

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d-二聚体的肺栓塞诊断可调整至临床概率。

背景回顾性分析表明，在临床前测验概率（C-PTP）低的患者中，d-二聚体水平低于1000 ng /毫升，而d-二聚体水平低于500 ng /毫升，从而排除了肺栓塞在中度C-PTP患者中。方法我们进行了一项前瞻性研究，其中在低C-PTP和d-二聚体水平低于1000 ng / ml或中度C-PTP和d -二聚体含量低于每毫升500 ng。所有其他患者均接受了胸部成像（通常是计算机断层扫描肺血管造影）。如果未诊断出肺栓塞，则患者不接受抗凝治疗。所有患者均随访3个月以检测静脉血栓栓塞。结果共有2017例患者入组并进行了评估，其中7.4％的患者在初步诊断测试中出现肺栓塞。在1325名C-PTP低（1285名患者）或中度C-PTP（40名患者）且d-二聚体试验阴性（即分别<1000或<500 ng / ml）的患者中，没有人发生静脉血栓栓塞随访期间（95％置信区间[CI]，0.00至0.29％）。这些患者包括315例患者，这些患者的C-PTP低且d-二聚体水平为每毫升500至999 ng（95％CI，0.00至1.20％）。在最初没有诊断为肺栓塞且未接受抗凝治疗的所有1863名患者中，有1名患者（0.05％； 95％CI，0.01至0.30）患有静脉血栓栓塞。我们的诊断策略导致34.3％的患者使用了胸部成像，而排除C-PTP和d-二聚体水平低于500 ng / ml的肺栓塞的策略将导致51.9％的患者进行胸腔成像（差异为-17.6个百分点） ； 95％CI，-19.2至-15.9）。结论低C-PTP和d-二聚体水平低于1000 ng / ml的组合确定了一组在随访期间发生肺栓塞的风险较低的患者。（由加拿大卫生研究院和其他机构资助； PEGeD ClinicalTrials.gov编号，NCT02483442。）。结论低C-PTP和d-二聚体水平低于1000 ng / ml的组合确定了一组在随访期间发生肺栓塞的风险较低的患者。（由加拿大卫生研究院及其他机构资助； PEGeD ClinicalTrials.gov编号，NCT02483442。）。结论低C-PTP和d-二聚体水平低于1000 ng / ml的组合确定了一组在随访期间发生肺栓塞的风险较低的患者。（由加拿大卫生研究院和其他机构资助； PEGeD ClinicalTrials.gov编号，NCT02483442。）。