title: Performance of a new, rapid, automated immunoassay for the detection of anti-platelet factor 4/heparin complex antibodies.
abstract: Heparin-induced thrombocytopenia (HIT) is a life-threatening adverse reaction to heparin that must be identified quickly to determine appropriate anticoagulant therapy strategies. The most common antibodies involved in HIT are directed against platelet factor 4/heparin (PF4/H) complexes. Many methods for anti-PF4/H detection exist such as enzyme immunoassays (EIAs), which have been shown to exhibit high-negative predictive value allowing for the exclusion of HIT in the majority of suspected patients; however, most EIAs are performed in a batch mode, thereby delaying results to the physician. HemosIL HIT-Ab(PF4-H) is a new, rapid method for the detection of total immunoglobulin against PF4/H complexes on ACL TOP Family systems. The assay was evaluated in a multicentre study at three sites with 414 HIT-suspected patients. Using a cut-off value of 1.0 U/ml for HemosIL HIT-Ab(PF4-H), the new test was compared with Asserachrom HPIA. Results showed a co-positivity of 60.2% [95% confidence interval (CI) 48.9-70.8], co-negativity of 94.6% (95% CI 91.5-96.7), and overall agreement of 87.7% (95% CI 84.1-90.7). These results are comparable to other PF4/H antibody assays available; with the added benefit of full automation and on-demand testing which provides results at the critical moment when physicians are required to make clinical decisions regarding anticoagulant therapy.
authors.affiliation: Department of Haematology, Royal Brompton Hospital, London, UK. S.Davidson@rbht.nhs.uk
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Davidson
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Ortel
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Smith
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D000925:Anticoagulants / Q000009:adverse effects / Q000097:blood / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000097:blood*; D057205:Automation, Laboratory; D006493:Heparin / Q000009:adverse effects / Q000097:blood / Q000276:immunology*; D057166:High-Throughput Screening Assays; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood; D010978:Platelet Factor 4 / Q000097:blood* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013921:Thrombocytopenia / Q000097:blood / Q000139:chemically induced / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000925:Anticoagulants; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D010978:Platelet Factor 4; D006493:Heparin