Heparin-platelet factor 4 antibodies in intensive care patients: An observational seroprevalence study

Robert L. Levine, Georgene W. Hergenroeder, John L. Francis, Charles C. Miller, Marcie J. Hursting

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29 Scopus citations


Heparin-platelet factor 4 (PF4) antibodies mediate heparin-induced thrombocytopenia (HIT) and, irrespective of thrombocytopenia, are associated with poorer outcomes in some patients. The prevalence of heparin-PF4 antibodies, including platelet-activating ones, in patients in the medical, neurotrauma, or shock-trauma intensive care unit (ICU) remains unclear. In this single-center, observational study, heparin-PF4 antibodies (IgG/A/M) were measured by ELISA in 185 adults (median APACHE II score, 16) admitted to the medical (n = 27), neurotrauma (n = 96), or shock-trauma (n = 62) ICU and after 7 ± 2 days. Seropositive patients and heparin-treated patients with unexplained, new-onset thrombocytopenia were also tested for platelet-activating antibodies using a serotonin release assay(SRA). Of185 patients, seropositivity occurred in 20 patients (10.8%; 95% CI 6.7-16.2%) at admission and 54 (29.2%, 95% CI 22.8-36.3%) after 7 days (P < 0.001). Platelet-activating antibodies occurred in 4 seropositive patients at admission and 9 seropositive patients after 7 days (including in 1 patient at each assessment), each without thrombocytopenia or new thrombosis. Of 12 seropositive patients with platelet-activating antibodies, 6 had an ELISA optical density (OD) >1.0. ELISA-positive, SRA-negative, suspected HIT occurred in 1 patient. Heparin-PF4 antibodies are present in 10.8% of medical, neurotrauma, or shocktrauma ICU patients at admission and increase significantly to 29.2% within 7 days. Approximately 17-20% of seropositive ICU patients, often those with an ELISA OD <1.0, have platelet-activating heparin-PF4 antibodies.

Original languageEnglish (US)
Pages (from-to)142-148
Number of pages7
JournalJournal of Thrombosis and Thrombolysis
Issue number2
StatePublished - Aug 2010


  • Antibody
  • Heparin
  • Heparin-induced thrombocytopenia
  • Platelet factor 4
  • Prevalence

ASJC Scopus subject areas

  • Hematology
  • Cardiology and Cardiovascular Medicine


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