Journal article

Publication year: 2011

Pages: 345-348

Journal: Thrombosis Research: Vascular Obstruction, Hemorrhage and Hemostasis

Volume number: 127

Issue number: 4

ISSN: 0049-3848

DOI Link: https://doi.org/10.1016/j.thromres.2010.12.001

Publisher: Elsevier

Abstract: 

Background: The in vitro demonstration of antibodies against platelet factor-4/heparin (PF4/hep) complexes is an important contribution to the diagnosis of heparin-induced thrombocytopenia (HIT). The use of PF4/hep IgG-specific immunoassays enhances the specificity of HIT-investigations without any impairment of the sensitivity. Several IgG-specific immunoassays with different origin and structure of the target antigen-complex are commercially available.

Methods: Using a retrospective cohort consisting of 459 patients suspected to have HIT, we compared the performance characteristics of two commercially available IgG-specific immunoassays, GTI- (Genetic Testing Institute) and HIA-IgG-ELISA (Hyphen Biomed Research).

Results: PF4/hep antibodies were detected in 85 and 81 sera using GTI- and HIA-IgG-ELISA, respectively. OD values and clinical likelihood of patients who tested positive in one assay only were significantly lower than in those who tested positive in both immunoassays. Both IgG-specific assays showed high negative predictive values (100%) and similar but unsatisfactory positive predictive values, determined by a minimum clinical score of 5 and a positive HIPA result (41% and 43%, respectively). The implementation of a confirmatory step using excessive heparin increased the PPV of both assays, but results in a reduction of NPV in HIA-IgG-ELISA.

Conclusions: The detection of IgG antibodies alone improves the clinical usefulness of immunoassays. However, functional assays remain indispensable to avoid the overdiagnosis of HIT caused by the detection of IgG non-platelet activating antibodies. The OD value in IgG immunoassays appears to correlate with the clinical relevance of the antibodies and might be used as a predictive parameter in the assessment of HIT. (C) 2010 Elsevier Ltd. All rights reserved.

Harvard Citation style: Bakchoul, T., Giptner, A., Bein, G., Santoso, S. and Sachs, U. (2011) Performance characteristics of two commercially available IgG-specific immunoassays in the assessment of heparin-induced thrombocytopenia (HIT), Thrombosis Research: Vascular Obstruction, Hemorrhage and Hemostasis, 127(4), pp. 345-348. https://doi.org/10.1016/j.thromres.2010.12.001

APA Citation style: Bakchoul, T., Giptner, A., Bein, G., Santoso, S., & Sachs, U. (2011). Performance characteristics of two commercially available IgG-specific immunoassays in the assessment of heparin-induced thrombocytopenia (HIT). Thrombosis Research: Vascular Obstruction, Hemorrhage and Hemostasis. 127(4), 345-348. https://doi.org/10.1016/j.thromres.2010.12.001