40. Heparin-Induced Thrombocytopenia

  1. Kandice Kottke-Marchant MD, PhD3,4,5 and
  2. Bruce H. Davis MD6
  1. Sixten Selleng MD1 and
  2. Andreas Greinacher MD2

Published Online: 8 AUG 2012

DOI: 10.1002/9781444398595.ch40

Laboratory Hematology Practice

Laboratory Hematology Practice

How to Cite

Selleng, S. and Greinacher, A. (2012) Heparin-Induced Thrombocytopenia, in Laboratory Hematology Practice (eds K. Kottke-Marchant and B. H. Davis), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781444398595.ch40

Editor Information

  1. 3

    Pathology & Laboratory Medicine Institute, Cleveland, OH, USA

  2. 4

    Department of Pathology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA

  3. 5

    Hemostasis and Thrombosis, Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH, USA

  4. 6

    Trillium Diagnostics, LLC, Bangor, ME, USA

Author Information

  1. 1

    Klinik für Anasthesiologie und Intensivmedizin, Ernst-Moritz-Arndt Universität, Greifswald, Germany

  2. 2

    Institut für Immunologie und, Transfusionsmedizin, Ernst-Moritz-Arndt Universität, Greifswald, Germany

Publication History

  1. Published Online: 8 AUG 2012
  2. Published Print: 10 APR 2012

ISBN Information

Print ISBN: 9781405162180

Online ISBN: 9781444398595

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Keywords:

  • heparin-induced thrombocytopenia;
  • pathogenesis;
  • laboratory testing;
  • diagnosis

Summary

Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating immunoglobulin (Ig)G antibodies that recognize multimolecular complexes of platelet factor 4 (PF4) bound to heparin or other polyanions. Clinical HIT occurs only among a subset of those patients who test positive for anti-PF4/heparin antibodies, and is most likely in those who test positive for anti-PF4/heparin antibodies of the IgG class with platelet-activating properties demonstrated by a positive functional assay. As most assays have a high sensitivity for anti-PF4/heparin antibodies, a negative test generally excludes HIT, carrying a high negative predictive value especially in a setting of a low pretest probability. The magnitude of a positive test result correlates with greater likelihood of HIT. Therefore, a combined diagnostic approach that considers the clinical picture and the magnitude of a positive test result is recommended for accurate diagnosis of HIT.