American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia

Blood Adv. 2018 Nov 27;2(22):3360-3392. doi: 10.1182/bloodadvances.2018024489.


Background: Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction mediated by platelet-activating antibodies that target complexes of platelet factor 4 and heparin. Patients are at markedly increased risk of thromboembolism.

Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about diagnosis and management of HIT.

Methods: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

Results: The panel agreed on 33 recommendations. The recommendations address screening of asymptomatic patients for HIT, diagnosis and initial management of patients with suspected HIT, treatment of acute HIT, and special situations in patients with acute HIT or a history of HIT, including cardiovascular surgery, percutaneous cardiovascular intervention, renal replacement therapy, and venous thromboembolism prophylaxis.

Conclusions: Strong recommendations include use of the 4Ts score rather than a gestalt approach for estimating the pretest probability of HIT and avoidance of HIT laboratory testing and empiric treatment of HIT in patients with a low-probability 4Ts score. Conditional recommendations include the choice among non-heparin anticoagulants (argatroban, bivalirudin, danaparoid, fondaparinux, direct oral anticoagulants) for treatment of acute HIT.

Publication types

  • Practice Guideline

MeSH terms

  • Administration, Oral
  • Anticoagulants / adverse effects*
  • Anticoagulants / therapeutic use
  • Arginine / analogs & derivatives
  • Cardiovascular Surgical Procedures
  • Chondroitin Sulfates / therapeutic use
  • Dermatan Sulfate / therapeutic use
  • Evidence-Based Medicine
  • Fondaparinux / therapeutic use
  • Heparin / adverse effects*
  • Heparin / therapeutic use
  • Heparitin Sulfate / therapeutic use
  • Hirudins
  • Humans
  • Peptide Fragments / therapeutic use
  • Pipecolic Acids / therapeutic use
  • Platelet Count
  • Recombinant Proteins / therapeutic use
  • Renal Replacement Therapy
  • Sulfonamides
  • Thrombocytopenia / chemically induced
  • Thrombocytopenia / pathology*
  • Venous Thromboembolism / diagnosis
  • Venous Thromboembolism / drug therapy*


  • Anticoagulants
  • Hirudins
  • Peptide Fragments
  • Pipecolic Acids
  • Recombinant Proteins
  • Sulfonamides
  • Dermatan Sulfate
  • Heparin
  • Chondroitin Sulfates
  • Heparitin Sulfate
  • Arginine
  • danaparoid
  • argatroban
  • Fondaparinux
  • bivalirudin