Izban K F, Lietz H W, Hoppensteadt D A, Jeske W P, Fareed J, Bakhos M, Walenga J M
Department of Thoracic and Cardiovascular Surgery, Loyola University Medical Center, Maywood, Illinois 60153, USA.
Semin Thromb Hemost. 1999;25 Suppl 1:51-6.
Serum samples from 105 patients with suspected heparin-induced thrombocytopenia (HIT) were evaluated using the 14C-serotonin release assay (SRA), considered the "gold standard" for the diagnosis of HIT, and two enzyme-linked immunosorbent assays (ELISA) that measure anti-platelet factor (PF) 4/heparin antibodies to determine the performance characteristics of the newly available ELISA assays. Relative to the SRA, the sensitivity and specificity of the Asserachrom HPIA assay were 73% and 77%, respectively, in this population of patients. The sensitivity and specificity of the GTI-HAT assay were 60% and 93%, respectively. In serum negative by SRA, GTI-HAT and HPIA detected antibodies in 9% and 25%, respectively. Antibodies were detected by HPIA in 18% of the sera negative by both SRA and GTI-HAT. In a second study, samples evaluated from patients (n = 10) treated for established thrombosis with a low-molecular-weight heparin and who had no decrease in platelet counts, showed a weak antibody titer in 50% of the patients after 12 days of therapy by GTI-HAT, whereas the HPIA identified a strong antibody titer in 75% of the patients after 4 days. These data suggest that the currently available ELISA methods for the detection of anti-PF4/heparin antibodies offer a limited sensitivity and specificity in comparison to SRA. The ELISA assays on their own are thus of limited value for the laboratory diagnosis of HIT. SRA-positive sera do not always have positive antibody titers, and antibodies can be present in SRA-negative sera. Furthermore, these data show that ELISA methods differ in their relative sensitivities and specificities for the detection of anti-PF4/heparin antibodies.
采用被视为肝素诱导的血小板减少症（HIT）诊断“金标准”的¹⁴C - 5 - 羟色胺释放试验（SRA）以及两种检测抗血小板因子（PF）4/肝素抗体的酶联免疫吸附测定（ELISA），对105例疑似HIT患者的血清样本进行评估，以确定新可用ELISA检测方法的性能特征。在该患者群体中，相对于SRA，Asserachrom HPIA检测的灵敏度和特异性分别为73%和77%。GTI - HAT检测的灵敏度和特异性分别为60%和93%。在SRA检测为阴性的血清中，GTI - HAT和HPIA分别在9%和25%的血清中检测到抗体。在SRA和GTI - HAT均为阴性的血清中，HPIA在18%的血清中检测到抗体。在第二项研究中，对10例接受低分子量肝素治疗已确诊血栓形成且血小板计数未降低的患者样本进行评估，结果显示，治疗12天后，GTI - HAT在50%的患者中检测到弱抗体滴度，而HPIA在4天后在75%的患者中检测到强抗体滴度。这些数据表明，与SRA相比，目前可用的用于检测抗PF4/肝素抗体的ELISA方法灵敏度和特异性有限。因此，ELISA检测本身对HIT的实验室诊断价值有限。SRA阳性血清并不总是具有阳性抗体滴度，且抗体可存在于SRA阴性血清中。此外，这些数据表明ELISA方法在检测抗PF4/肝素抗体的相对灵敏度和特异性方面存在差异。
