A sensitive and specific functional flow cytometric assay for the diagnosis of heparin-induced thrombocytopenia

Br J Haematol. 1997 Sep;98(3):648-56. doi: 10.1046/j.1365-2141.1997.2613077.x.


A functional flow cytometric assay (FCA) for the immediate diagnosis of heparin-induced thrombocytopenia (HIT), with simultaneous compatibility testing for alternative anticoagulant therapies, has been developed to provide rapid and reliable results which effectively support patient management. The assay provides results within 1-2 h, uses readily available non-radioactive reagents, and employs standard equipment. Using the highly sensitive annexin V protein probe, the method detects activated platelets induced by heparin immune-complexes, with 300-fold increased binding to activated platelets. Twenty-five samples from patients clinically-suspected of having HIT (131 tests) and 10 normal control (NG) samples (36 tests) were simultaneously tested with unfractionated heparin (UH) and low-molecular-weight heparin (LMWH), and by the radioactive serotonin-release assay (SRA) (62 and 16 tests respectively). The FCA highly correlated with the SRA, showing 100% specificity and 95% sensitivity. Moreover, the FCA exhibited higher resolution between positive and negative samples (an average value of 8.6-fold the NC versus 4.0-fold the NC by SRA). The LMWH showed concordant results with UH (r = 0.95). We conclude that the functional FCA for HIT is practical, specific and sensitive, thereby permitting the rapid diagnosis of HIT and the suitability of alternative therapies.

MeSH terms

  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Heparin / adverse effects*
  • Heparin, Low-Molecular-Weight / adverse effects
  • Humans
  • Sensitivity and Specificity
  • Thrombocytopenia / chemically induced
  • Thrombocytopenia / diagnosis*


  • Heparin, Low-Molecular-Weight
  • Heparin