Harper P, Marson C, Grimmer A, Monahan K, Humm G, Baker B
Department of Clinical Haematology and Medlab Central, Palmerston North Hospital.
N Z Med J. 2001 Feb 23;114(1126):61-4.
Several clinical studies have proposed using d-dimer as an initial screening test to exclude thrombosis in cases of suspected (DVT). In published series, these assays have variable sensitivity, raising concerns that they may not be sufficiently robust for clinical practice. The aim of the study was to examine the sensitivity of two commercially available d-dimer assays and to assess their value and safety as initial screening tests in suspected DVT.
In this prospective study, blood samples were collected for d-dimer measurement (SimpliRED assay and IL test d-dimer) in all patients presenting to the emergency department over a twelve month period. All patients underwent compression ultrasound scanning as the primary diagnostic procedure.
235 patients were included in the study. 51(22.8%) had a DVT confirmed on ultrasound. The SimpliRED assay was positive in only 33 cases, with seventeen cases of confirmed DVT giving a negative result (six cases with proximal vein thrombosis). Assay sensitivity was 66%, with a negative predictive value of 88.9%. The IL test gave three false negatives (all below knee thromboses) giving assay sensitivity and negative predictive value of 94.1% and 96.8% respectively.
The precise role of d-dimer testing in the diagnosis of venous thrombosis has yet to be established. From our results and a review of published series, we conclude that the SimpliRED assay is too insensitive to use as a reliable exclusion test in cases of suspected DVT, however, the more sensitive automated IL test d-dimer may have a role in the initial assessment. We propose that the IL d-dimer test is used in conjunction with a pre-test probability score to identify patients at low risk of DVT and recommend that this approach is tested in a clinical study before introduction into practice.
多项临床研究提出将D - 二聚体用作初步筛查试验，以排除疑似深静脉血栓形成（DVT）病例中的血栓形成。在已发表的系列研究中，这些检测方法的敏感性各不相同，这引发了人们对它们在临床实践中可能不够可靠的担忧。本研究的目的是检验两种市售D - 二聚体检测方法的敏感性，并评估它们作为疑似DVT初步筛查试验的价值和安全性。
在这项前瞻性研究中，在为期十二个月的时间里，对所有到急诊科就诊的患者采集血样进行D - 二聚体检测（SimpliRED检测法和IL检测D - 二聚体）。所有患者均接受加压超声扫描作为主要诊断程序。
235例患者纳入研究。51例（22.8%）经超声证实患有DVT。SimpliRED检测法仅在33例中呈阳性，17例确诊DVT病例检测结果为阴性（6例为近端静脉血栓形成）。检测敏感性为66%，阴性预测值为88.9%。IL检测出现3例假阴性（均为膝下血栓形成），检测敏感性和阴性预测值分别为94.1%和96.8%。
D - 二聚体检测在静脉血栓形成诊断中的精确作用尚未确立。根据我们的结果以及对已发表系列研究的综述，我们得出结论，SimpliRED检测法在疑似DVT病例中用作可靠的排除试验过于不敏感，然而，更敏感的自动化IL检测D - 二聚体可能在初步评估中发挥作用。我们建议将IL D - 二聚体检测与检测前概率评分结合使用，以识别DVT低风险患者，并建议在引入临床实践之前在临床研究中对这种方法进行检验。
