title: Diagnostic accuracy of rapid immunoassays for heparin-induced thrombocytopenia. A systematic review and meta-analysis.
abstract: The platelet factor 4/heparin ELISA has limited specificity for heparin-induced thrombocytopenia (HIT) and frequently does not provide same-day results. Rapid immunoassays (RIs) have been developed which provide results in 30 minutes or less. We conducted a systematic review and meta-analysis to evaluate the diagnostic accuracy of RIs for HIT. We searched the literature for studies in which samples from patients with suspected HIT were tested using a RI and a functional assay against which the performance of the RI could be measured. We performed sensitivity analyses of studies that directly compared different RIs with each other and with ELISAs. Estimates of sensitivity and specificity for each RI were calculated. Twenty-three articles, collectively involving six different RIs, met eligibility criteria. All RIs exhibited high sensitivity (0.96 to 1.00); there was wider variability in specificity (0.68 to 0.94). Specificity of the IgG-specific chemiluminescent assay (IgG-CA) was greater than the polyspecific chemiluminescent assay [0.94 (95 %CI 0.89-0.99) vs 0.82 (0.77-0.87)]. The particle gel immunoassay demonstrated greater specificity than the polyspecific ELISA [0.96 (0.95-0.97) vs 0.91 (0.89-0.92)]. The IgG-CA and lateral flow immunoassay [0.94 (0.91-0.97)] exhibited greater specificity than the IgG-specific ELISA [0.86 (0.82-0.90)]. Given their high sensitivity and rapid turnaround time, RIs are a reliable means of excluding HIT at the point-of-care in patients with low or intermediate clinical probability. Additionally, some RIs have greater specificity than HIT ELISAs. In summary, IgG-specific RIs appear to have improved diagnostic accuracy compared with ELISAs in patients with suspected HIT and may reduce misdiagnosis and overtreatment.
authors.forename: Lova
authors.initials: L
authors.lastname: Sun
authors.forename: Phyllis A
authors.initials: PA
authors.lastname: Gimotty
authors.forename: Suvasini
authors.initials: S
authors.lastname: Lakshmanan
authors.affiliation: Adam Cuker, MD, MS, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA, Tel.: +1 215 615 6555, Fax: +1 215 615 6599, E-mail: adam.cuker@uphs.upenn.edu.
authors.forename: Adam
authors.initials: A
authors.lastname: Cuker
mesh_terms: D000906:Antibodies / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000706:statistics & numerical data; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D010978:Platelet Factor 4 / Q000276:immunology; D019095:Point-of-Care Systems; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000906:Antibodies; D010978:Platelet Factor 4; D006493:Heparin
keywords: Heparin; immunoassay; meta-analysis; review; thrombocytopenia