Warkentin Theodore E, Heddle Nancy M
Hamilton Regional Laboratory Medicine Program, Hamilton Health Sciences, Hamilton General Site, 237 Baron Street East, Hamilton, ON L8L 2X2, Canada.
Curr Hematol Rep. 2003 Mar;2(2):148-57.
Immune heparin-induced thrombocytopenia (HIT) is a distinct immunohematologic syndrome in which laboratory detection of the pathogenic HIT antibodies is diagnostically useful. Assays can be broadly classified as platelet activation assays (which detect HIT antibodies based on their characteristic platelet-activating properties) and antigen assays (which measure antibodies reactive against platelet factor 4 complexed with heparin or other polyanions). Available tests vary considerably in their sensitivity-specificity profiles for detecting the antibodies and in their predictive values. The high sensitivity of certain assays means that HIT can be readily ruled out (high negative predictive value). However, because heparin-treated patients often generate nonpathogenic antibodies, a positive test does not necessarily indicate clinical HIT. Laboratory methods for detecting HIT antibodies have undergone an evolution similar to that of red blood cell serology and which parallels the Goldilocks tale, that is, progression from too insensitive (too hard) to too sensitive (too soft) to "just right." However, optimal diagnostic information requires that laboratory test results be interpreted in the appropriate clinical context.
免疫性肝素诱导的血小板减少症（HIT）是一种独特的免疫血液学综合征，其中致病性HIT抗体的实验室检测具有诊断价值。检测方法大致可分为血小板活化检测（基于其特征性的血小板活化特性检测HIT抗体）和抗原检测（检测与肝素或其他多阴离子复合的血小板因子4反应的抗体）。现有检测方法在检测抗体的敏感性-特异性特征及其预测价值方面差异很大。某些检测方法的高敏感性意味着可以很容易地排除HIT（高阴性预测值）。然而，由于接受肝素治疗的患者经常产生非致病性抗体，检测结果呈阳性并不一定表明临床存在HIT。检测HIT抗体的实验室方法经历了与红细胞血清学类似的演变，这与《金发姑娘》的故事相似，即从过于不敏感（太硬）到过于敏感（太软）再到“刚刚好”。然而，最佳诊断信息需要在适当的临床背景下解释实验室检测结果。
