Background: Patients with heparin-platelet factor 4 (PF4) antibodies, particularly platelet-activating ones, are at risk for heparin-induced thrombocytopenia if administered heparin. We determined the heparin-PF4 antibody prevalence in emergency department (ED) patients presenting with chest pain or symptoms of thrombosis. Methods: Admission samples from 324 ED patients with chest pain or symptoms of thrombosis were tested for heparin-PF4 antibodies and, if positive, platelet-activating antibodies. Results: Twenty-four (7.4%; 95% confidence interval, 4.8%-10.8%) patients had heparin-PF4 antibodies. Seropositivity occurred in 18 (9.2%) of 196 patients recently (≤6 months) hospitalized vs 6 (4.7%) of 128 not recently hospitalized (P = .19), and in 16/231 (6.9%) patients with chest pain vs 8/93 (8.6%) with other thrombosis (P = .64). Of 22 seropositive patients retested, 8 (7 recently hospitalized) had platelet-activating antibodies. Conclusion: Heparin-PF4 antibody prevalence is 7.4% in ED patients with chest pain or thrombosis, with ∼1 in 3 seropositive patients having platelet-activating antibodies. Alternative, nonheparin anticoagulation would be prudent in these at-risk patients.
ASJC Scopus subject areas
- Emergency Medicine