Wheeler H B, Hirsh J, Wells P, Anderson F A
Department of Surgery, University of Massachusetts Medical School, Worcester.
Arch Intern Med. 1994 Sep 12;154(17):1921-8.
We review the general principles that govern the clinical utility of diagnostic tests, particularly with respect to the diagnosis of deep vein thrombosis (DVT). We stress the importance of clinical probability of disease, which strongly influences the positive predictive value (true-positive rate) and negative predictive value (true-negative rate) of all diagnostic tests. In selecting a diagnostic procedure for DVT, the physician must first consider the clinical probability of disease and then the local accuracy of the test employed and its cost-effectiveness. In 75% to 80% of patients suspected to have DVT, clinical management can be based on the results of noninvasive tests, such as ultrasonography or impedance plethysmography (IPG), rather than venography. Ultrasonography has clear advantages over venography with respect to cost and patient comfort, and it defines the anatomic extent of the thrombus. It should be considered the new diagnostic standard for symptomatic DVT. Despite recent reports of lower sensitivity than previously reported, IPG remains an acceptable alternative to ultrasonography for symptomatic DVT in selected patients. Even if the recently reported lower sensitivity proves to be accurate, the probability of adverse clinical outcomes as a result of overlooked disease is still extremely low in patients with a low probability of DVT. The negative predictive value of IPG under these circumstances approaches 99%. Impedance plethysmography is also useful in patients with a high probability of DVT, in whom the positive predictive value may be as high as 97%. When the findings of IPG (or ultrasonography) are at variance with a strong clinical impression, venography should be considered, especially when there is a high clinical probability of disease and a negative noninvasive test result.
我们回顾了指导诊断试验临床应用的一般原则，特别是关于深静脉血栓形成（DVT）的诊断。我们强调疾病临床可能性的重要性，它对所有诊断试验的阳性预测值（真阳性率）和阴性预测值（真阴性率）有很大影响。在选择DVT的诊断方法时，医生必须首先考虑疾病的临床可能性，然后是所采用试验的局部准确性及其成本效益。在75%至80%疑似患有DVT的患者中，临床管理可以基于非侵入性试验的结果，如超声检查或阻抗体积描记法（IPG），而不是静脉造影。超声检查在成本和患者舒适度方面比静脉造影有明显优势，并且它能确定血栓的解剖范围。它应被视为有症状DVT的新诊断标准。尽管最近有报道称其敏感性低于先前报道，但对于选定的有症状DVT患者，IPG仍然是超声检查的可接受替代方法。即使最近报道的较低敏感性被证明是准确的，在DVT可能性低的患者中，因疾病被漏诊而导致不良临床结局的概率仍然极低。在这种情况下，IPG的阴性预测值接近99%。阻抗体积描记法对DVT可能性高的患者也有用，其阳性预测值可能高达97%。当IPG（或超声检查）的结果与强烈的临床印象不一致时，应考虑进行静脉造影，特别是当疾病临床可能性高且非侵入性试验结果为阴性时。
