Platelet factor 4/heparin antibody (IgG/M/A) in healthy subjects: a literature analysis of commercial immunoassay results.
OBJECTIVE
We determined the seroprevalence of platelet factor 4 (PF4)/heparin antibodies in healthy subjects.


METHODS
A literature search identified studies in which healthy subjects were evaluated using commercial immunoassays for PF4/heparin antibody (IgG/M/A). Proportions of test-positive subjects were calculated, by assay.


RESULTS
Across 11 eligible studies, 860 healthy subjects were tested using the Stago enzyme-linked immunosorbent assay (ELISA) (nine studies), GTI ELISA (three studies), and/or DiaMed particle gel immunoassay (PGIA) (three studies). Seropositivity occurred in 17 of 790 (2.2%, 95% CI, 1.1-3.2%) subjects by Stago ELISA, one of 100 (1.0%, 95% CI, 0-3.0%) subjects by GTI ELISA, and three of 70 (4.3%, 95% CI, 0-9.0%) subjects by PGIA (P > 0.20). Of seven seropositive subjects tested further, none had platelet-activating antibodies.


CONCLUSIONS
Commercial immunoassays detect PF4/heparin antibody in 1.0-4.3% of healthy subjects. Because this "background" prevalence overlaps seropositivity rates in heparin-treated patients in various clinical settings, normality cut-offs may require refinement.
Arepally
Gowthami M
GM
Division of Hematology, Duke University Medical Center, DUMC Box 3486, Room 304 Sands Building, Research Drive, Durham, NC 27710, USA. arepa001@mc.duke.edu
Hursting
Marcie J
MJ
D000906:Antibodies / Q000097:blood*; D000925:Anticoagulants / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006493:Heparin / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D010978:Platelet Factor 4 / Q000276:immunology*; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D015203:Reproducibility of Results; D016036:Seroepidemiologic Studies
D000906:Antibodies; D000925:Anticoagulants; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic; D010978:Platelet Factor 4; D006493:Heparin