Potential Impact of Adjusting the Threshold of the Quantitative D-dimer Based on Pretest Probability of Acute Pulmonary Embolism
Potential Impact of Adjusting the Threshold of the Quantitative D-dimer Based on Pretest Probability of Acute Pulmonary Embolism
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DOI：
10.1111/j.1553-2712.2009.00368.x
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发表时间：
2009-04-01
影响因子：
4.4
通讯作者：
Kline, Jeffrey A.
中科院分区：
文献类型：
--
作者：
Kabrhel, Christopher;Courtney, D. Mark;Kline, Jeffrey A.
D-二聚体检测对疑似肺栓塞 (PE) 的效用可能会受到检测特异性的限制。作者测试了是否可以根据 PE 的预测概率 (PTP) 改变定量 D-二聚体的阈值，以提高特异性，同时保持阴性预测值 (NPV) > 99%。这是一项针对美国急诊科 (ED) 患者的前瞻性、观察性多中心研究。符合条件的患者接受了一项诊断研究，以评估可能的 PE。 PTP 由临床医生的非结构化估计和 Wells 评分确定。使用五种不同的 D-二聚体测定。 D-二聚体测试性能使用 1) 标准阈值和 2) 可变阈值进行测量：标准阈值的两倍（对于低 PTP 患者）、等于（中 PTP 患者）或一半（高 PTP 患者）。 45 天内发生静脉血栓栓塞 (VTE) 需要阳性成像并决定治疗。作者招募了 7,940 名进行 PE 检测的患者，临床医生为 4,357 名 (55%) 患者进行了定量 D-二聚体检测，这些患者的 PTP 分布如下：低 (74%)、中 (21%) 或高 (4%)。在标准临界值下，在所有 PTP 层中，定量 D-二聚体检测的测试灵敏度为 94%（95% 置信区间 [CI] = 91% 至 97%），特异性为 58%（95% CI = 56% 至 60%），NPV 为 99.5%（95% CI = 99.1% 至 99.7%）。如果使用可变截止值，总体敏感性将为 88%（95% CI = 83% 至 92%），特异性为 75%（95% CI = 74% 至 76%），NPV 99.1%（95% CI = 98.7% 至 99.4%）。这个大型多中心观察样本表明，急诊医学临床医生目前在大多数接受 D-二聚体测试的患者中订购了 D-二聚体。 PE，其中中PTP和高PTP比例较大。根据 PTP 改变 D-二聚体的截止值可以提高特异性，而 NPV 不会明显降低。
The utility of D-dimer testing for suspected pulmonary embolism (PE) can be limited by test specificity. The authors tested if the threshold of the quantitative D-dimer can be varied according to pretest probability (PTP) of PE to increase specificity while maintaining a negative predictive value (NPV) of > 99%.This was a prospective, observational multicenter study of emergency department (ED) patients in the United States. Eligible patients had a diagnostic study ordered to evaluate possible PE. PTP was determined by the clinician's unstructured estimate and the Wells score. Five different D-dimer assays were used. D-dimer test performance was measured using 1) standard thresholds and 2) variable threshold values: twice (for low PTP patients), equal (intermediate PTP patients), or half (high PTP patients) of standard threshold. Venous thromboembolism (VTE) within 45 days required positive imaging plus decision to treat.The authors enrolled 7,940 patients tested for PE, and clinicians ordered a quantitative D-dimer for 4,357 (55%) patients who had PTPs distributed as follows: low (74%), moderate (21%), or high (4%). At standard cutoffs, across all PTP strata, quantitative D-dimer testing had a test sensitivity of 94% (95% confidence interval [CI] = 91% to 97%), specificity of 58% (95% CI = 56% to 60%), and NPV of 99.5% (95% CI = 99.1% to 99.7%). If variable cutoffs had been used the overall sensitivity would have been 88% (95% CI = 83% to 92%), specificity 75% (95% CI = 74% to 76%), and NPV 99.1% (95% CI = 98.7% to 99.4%).This large multicenter observational sample demonstrates that emergency medicine clinicians currently order a D-dimer in the majority of patients tested for PE, including a large proportion with intermediate PTP and high PTP. Varying the D-dimer's cutoff according to PTP can increase specificity with no measurable decrease in NPV.