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PubMed This is a summary of 14 peer-reviewed journal articles Updated
Hematology

Knowing Your Risk: The IPSET-Thrombosis Score

At a Glance

In Essential Thrombocythemia, 'risk' refers to the likelihood of developing a blood clot. Doctors use the IPSET-Thrombosis score, which evaluates your age, JAK2 mutation status, and history of blood clots, to classify your risk level and determine if you need medication or just observation.

In Essential Thrombocythemia (ET), “risk” doesn’t mean what it usually means in other cancers. When doctors talk about your risk level, they aren’t talking about how “aggressive” the cancer is or how much time you have left. Instead, they are strictly measuring the statistical likelihood that you might experience a blood clot (thrombosis) [1][2].

To calculate this, they use a tool called the Revised IPSET-Thrombosis score (International Prognostic Score for Essential Thrombocythemia). This score helps your care team strategically decide if you need medication to actively lower your platelet counts or if you can be safely monitored with just aspirin or observation [3][4].

The Three Variables of Risk

The IPSET score looks at three specific pieces of information about you to calculate your risk level:

  1. Age: Are you over the age of 60? [3]
  2. JAK2 Mutation: Do you have the JAK2 V617F genetic mutation? [3][1]
  3. Prior Thrombosis: Have you ever had a major blood clot (like a stroke, heart attack, or deep vein thrombosis) in the past? [3][2]

The Four Risk Categories

Based on these three factors, you will fall into one of four categories. This category acts as the “compass” your doctor uses to guide your long-term treatment plan.

Risk Category Criteria Typical Management Approach
Very Low Age ≤\leq 60, no JAK2 mutation, and no history of clots. [3] Often just observation or low-dose aspirin [3][4].
Low Age ≤\leq 60, positive for JAK2 mutation, and no history of clots. [3] Low-dose aspirin is usually recommended [5][1].
Intermediate Age over 60, no JAK2 mutation, and no history of clots. [3] Low-dose aspirin; cytoreductive (cell-lowering) meds may be optional [3][5].
High History of clots OR age over 60 with a JAK2 mutation. [3] Cytoreductive meds (like hydroxyurea or interferon) plus aspirin [3][6].

Why Your Category Matters

Understanding your category helps you and your doctor balance the benefits of treatment against the potential daily side effects of medications.

  • Preventing Over-treatment: If you are in the “Very Low” or “Low” risk groups, your risk of a major blood clot is very small. In these cases, taking strong medications to lower your platelets might cause more adverse side effects than the benefits they provide [7][8].
  • Targeting High Risk: If you are in the “High” risk group, the benefit of lowering your platelet count with medication heavily outweighs the risk of side effects, because preventing a second clot or a first major event is the absolute top priority [9][10][6].
  • The Role of General Health: It is important to note that if you have severe general cardiovascular risk factors—such as uncontrolled diabetes, severe high blood pressure, or a strong history of smoking—your doctor may recommend a more aggressive treatment approach (like cytoreductive therapy) even if your IPSET score technically puts you in a lower risk category [11][12].

A Note on Absolute Platelet Counts

You might notice that the actual platelet count number on your lab results (whether it’s 600,000 or 1.2 million) is not a part of the IPSET score [3]. While very high counts (usually over 1.5 million) may lead your doctor to start treatment regardless of your IPSET score to prevent bleeding complications, for most patients, your age and mutation status are much more accurate predictors of your safety than the specific number on your blood test [13][14][6].

Common questions in this guide

What does 'risk' mean in essential thrombocythemia?
In essential thrombocythemia, risk refers specifically to your statistical likelihood of experiencing a major blood clot, such as a stroke or deep vein thrombosis. It does not measure how aggressive the cancer is or how long you will live.
How is the IPSET-Thrombosis score calculated?
The score is calculated using three main factors: your age (whether you are over 60), if you have the JAK2 V617F genetic mutation, and whether you have a history of major blood clots. These factors group you into one of four risk categories.
Does my actual platelet count affect my IPSET risk score?
No, your absolute platelet count is not a factor in calculating your IPSET-Thrombosis score. However, if your count becomes extremely high, typically over 1.5 million, your doctor may recommend treatment regardless of your score to prevent bleeding complications.
What is the treatment for low-risk essential thrombocythemia?
Patients in the very low or low risk categories are typically managed with active observation or a daily low-dose aspirin. Because their risk of blood clots is minimal, avoiding strong medications helps prevent unnecessary side effects.
When do doctors prescribe cell-lowering medications for ET?
Cytoreductive medications, which actively lower platelet counts, are usually prescribed for patients in the high-risk category. They may also be considered for intermediate-risk patients or those with severe cardiovascular risk factors like uncontrolled diabetes or a history of smoking.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my exact age, mutation status, and medical history, what is my specific IPSET-Thrombosis risk category?
  2. 2.If I am in the 'Intermediate' category, what specific factors would push you to recommend starting cytoreductive medication versus just using aspirin?
  3. 3.Does my risk score change if my platelet count goes above a certain number, even if I feel perfectly fine?
  4. 4.How often should we re-evaluate my risk score as I get older or if my health changes?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (14)
  1. 1

    Polycythemia vera and essential thrombocythemia: 2021 update on diagnosis, risk-stratification and management.

    Tefferi A, Barbui T

    American journal of hematology 2020; (95(12)):1599-1613 doi:10.1002/ajh.26008.

    PMID: 32974939
  2. 2

    Essential thrombocythemia: 2024 update on diagnosis, risk stratification, and management.

    Tefferi A, Vannucchi AM, Barbui T

    American journal of hematology 2024; (99(4)):697-718 doi:10.1002/ajh.27216.

    PMID: 38269572
  3. 3

    Validation of the revised International Prognostic Score of Thrombosis for Essential Thrombocythemia (IPSET-thrombosis) in 585 Mayo Clinic patients.

    Haider M, Gangat N, Lasho T, et al.

    American journal of hematology 2016; (91(4)):390-4 doi:10.1002/ajh.24293.

    PMID: 26799697
  4. 4

    The Essential Thrombocythemia in 2020: What We Know and Where We Still Have to Dig Deep.

    Accurso V, Santoro M, Mancuso S, et al.

    Clinical medicine insights. Blood disorders 2020; (13()):2634853520978210 doi:10.1177/2634853520978210.

    PMID: 33447121
  5. 5

    Polycythemia vera and essential thrombocythemia: 2019 update on diagnosis, risk-stratification and management.

    Tefferi A, Barbui T

    American journal of hematology 2019; (94(1)):133-143 doi:10.1002/ajh.25303.

    PMID: 30281843
  6. 6

    Case report: Peri-procedural hydroxyurea helps minimize bleeding in patients with Essential Thrombocythemia associated with acquired von Willebrand syndrome.

    Kogan L, Price R, Kotchetkov R

    Frontiers in oncology 2024; (14()):1326209 doi:10.3389/fonc.2024.1326209.

    PMID: 38361779
  7. 7

    Validation of thrombotic risk factors in 1381 patients with essential thrombocythaemia: A multicentre retrospective real-life study.

    Stuckey R, Ianotto JC, Santoro M, et al.

    British journal of haematology 2022; (199(1)):86-94 doi:10.1111/bjh.18387.

    PMID: 35906782
  8. 8

    Application of prognostic score IPSET-thrombosis in patients with essential thrombocythemia of a Brazilian public service.

    Navarro LM, Trufelli DC, Bonito DR, et al.

    Revista da Associacao Medica Brasileira (1992) 2016; (62(7)):647-651 doi:10.1590/1806-9282.62.07.647.

    PMID: 27925044
  9. 9

    Essential Thrombocythemia: The Dermatologic Point of View.

    Cozzani E, Iurlo A, Merlo G, et al.

    Clinical lymphoma, myeloma & leukemia 2015; (15(12)):739-47.

    PMID: 26432058
  10. 10

    A review of essential thrombocythemia and its complications.

    Babakhanlou R, Masarova L, Verstovsek S

    Clinical advances in hematology & oncology : H&O 2023; (21(2)):76-84.

    PMID: 36780473
  11. 11

    Validation of previous prognostic models for thrombosis and exploration of modified models in patients with essential thrombocythemia.

    Hashimoto Y, Nakamae H, Tanaka T, et al.

    European journal of haematology 2018; (101(4)):508-513 doi:10.1111/ejh.13136.

    PMID: 29971894
  12. 12

    Reevaluation of cardiovascular risk factors for thrombotic events in 580 Japanese patients with essential thrombocythemia.

    Furuya C, Hashimoto Y, Morishita S, et al.

    Journal of thrombosis and thrombolysis 2023; (55(2)):263-272 doi:10.1007/s11239-022-02751-0.

    PMID: 36484956
  13. 13

    Management of extreme thrombocytosis in myeloproliferative neoplasms: an international physician survey.

    Koren-Michowitz M, Lavi N, Ellis MH, et al.

    Annals of hematology 2017; (96(1)):87-92 doi:10.1007/s00277-016-2826-4.

    PMID: 27734130
  14. 14

    Hemorrhage in Essential Thrombocythemia or Polycythemia Vera: Epidemiology, Location, Risk Factors, and Lessons Learned from the Literature.

    Nicol C, Lacut K, Pan-Petesch B, et al.

    Thrombosis and haemostasis 2021; (121(5)):553-564 doi:10.1055/s-0040-1720979.

    PMID: 33186994

This page explains the IPSET-Thrombosis score for educational purposes only. Always consult your hematologist to determine your specific risk category and the safest long-term treatment plan for your situation.

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