Haas Fred J L M, Schutgens Roger E G, Biesma Douwe H
Department of Clinical Chemistry, St. Antonius Hospital, 3430 EM Nieuwegein, The Netherlands.
Am J Hematol. 2009 Aug;84(8):488-91. doi: 10.1002/ajh.21455.
A normal D-dimer (DD) concentration for the exclusion of deep venous thrombosis (DVT) has a low specificity in older patients and compression ultrasonography is often required. Three D-dimer assays, STA Liatest, Tina-quant, and Innovance, are evaluated in symptomatic outpatients suspected for DVT with emphasis on its performance in older patients by using different cut-off levels. This study includes 466 outpatients suspected for having DVT. The diagnostic accuracy, measured as sensitivity and area under the curve of the receiver operation characteristic curve is good for all DD assays. The specificity of the DD assays combined with a low pretest probability varies from 42.6 to 51.5%. The specificity of the three DD assays in patients > or = 60 years varies, however, between 24.6 and 40.9%. Several cut-off values in different age-subgroups are studied. For patients < 60 years, the most accurate cut-off value is 500 microg/L for all DD assays. For patients > or = 60 years, a threshold of 750 microg/L has the best results with NPV of 100% for all assays and specificity of 48.5% (STA Liatest), 60.6% (Tina-quant), and 49.2% (Innovance), respectively. For the three assays, the number needed to test (NNT) decreases in both subgroups of patients compared to the standard algorithm. A cut-off level of 750 microg/L for patients > or = 60 years improves the clinical performance of DD assays in combination with the PTP score without the loss of NPV. The NNT improves substantially with an age-adapted algorithm.
正常的D - 二聚体（DD）浓度用于排除深静脉血栓形成（DVT）在老年患者中特异性较低，通常需要进行加压超声检查。对三种D - 二聚体检测方法，即STA Liatest、Tina - quant和Innovance，在疑似DVT的有症状门诊患者中进行评估，重点是通过使用不同的临界值来观察其在老年患者中的表现。本研究纳入了466例疑似患有DVT的门诊患者。以敏感性和接受者操作特征曲线下面积衡量的诊断准确性，对所有DD检测方法而言都较好。DD检测方法与低验前概率相结合时，特异性在42.6%至51.5%之间。然而，在年龄≥60岁的患者中，这三种DD检测方法的特异性在24.6%至40.9%之间变化。研究了不同年龄亚组的几个临界值。对于年龄<60岁的患者，所有DD检测方法最准确的临界值为500μg/L。对于年龄≥60岁的患者，750μg/L的临界值效果最佳，所有检测方法的阴性预测值均为100%，特异性分别为48.5%（STA Liatest）、60.6%（Tina - quant）和49.2%（Innovance）。对于这三种检测方法，与标准算法相比，两个患者亚组中需要检测的病例数（NNT）均减少。对于年龄≥60岁的患者，750μg/L的临界值与PTP评分相结合可改善DD检测方法的临床性能，且不会损失阴性预测值。采用年龄适应性算法时，NNT有显著改善。
