National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Heparin-induced thrombocytopenia



Other Names:
HIT; Heparin-induced thrombocytopenia
Categories:

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets (thrombocytopenia). HIT is usually an immune response which typically occurs 4-10 days after exposure to heparin; it can lead to serious complications and be life-threatening. This condition occurs in up to 5% of those who are exposed to heparin. Characteristic signs of HIT are a drop in platelet count of  greater than 50% and/or the formation of new blood clots during heparin therapy.  The first step of treatment is to discontinue and avoid all heparin products immediately. Often, affected individuals require another medicine to prevent blood clotting (anticoagulants). [1][2]
Last updated: 5/3/2012

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 14 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Autoimmune thrombocytopenia 0001973
Hypercoagulability 0100724
Thromboembolism 0001907
30%-79% of people have these symptoms
Arterial thrombosis
Blood clot in artery
0004420
Deep venous thrombosis
Blood clot in a deep vein
0002625
Increased serum serotonin 0003144
5%-29% of people have these symptoms
Cerebral ischemia
Disruption of blood oxygen supply to brain
0002637
Disseminated intravascular coagulation 0005521
Increased inflammatory response 0012649
Mesenteric venous thrombosis 0030248
Myocardial infarction
Heart attack
0001658
Pulmonary embolism
Blood clot in artery of lung
0002204
Stroke 0001297
1%-4% of people have these symptoms
Abnormal onset of bleeding 0040231
Showing of 14 |
Last updated: 7/1/2020

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

  • Lepirudin (Brand name: Refluden) - Manufactured by Hoechst Marion Roussel
    FDA-approved indication: For anticoagulation in patients with heparin-induced thrombocytopenia and associated thromboembolic disease in order to prevent further thromboembolic complications.
    National Library of Medicine Drug Information Portal

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes nonimmune heparin-associated thrombocytopenia (due to the direct interaction of heparin with circulating platelets, occurring during the first days of heparin administration), as well as postoperative hemodilution, sepsis, non-HIT drug-induced thrombocytopenia, disseminated intravascular coagulation, and multiorgan system failure.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Heparin-induced thrombocytopenia. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The National Heart, Lung, and Blood Institute (NHLBI) has information on this topic. NHLBI is part of the National Institutes of Health and supports research, training, and education for the prevention and treatment of heart, lung, and blood diseases.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Heparin-induced thrombocytopenia. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Greinacher A & Lubenow N. Heparin-induced thrombocytopenia. Orphanet. 2003; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=3325. Accessed 5/3/2012.
  2. Heparin-induced thrombocytopenia. Medscape Reference. 2011; http://emedicine.medscape.com/article/1357846-overview. Accessed 5/3/2012.