Guidelines for diagnosing and treating thrombotic thrombocytopenic purpura (TTP)

The International Society on Thrombosis and Haemostasis (ISTH) published guidelines are the first comprehensive, evidence-based, international guidelines on the diagnosis, treatment, and management of TTP.1

See the ISTH Guidelines
See the ISTH Guidelines
The ISTH Guidelines for Diagnosis and Treatment were published July 2020

Most recent publication

The 2020 ISTH Guidelines had a focused update in November 2025.

  • The ISTH guidelines for diagnosis and treatment of TTP were first published in 20201
  • Treatment guidelines were updated in 2025 to account for new data2
    • The 2025 guidelines reinforced the guidance first published in 2020 for acquired thrombotic thrombocytopenic purpura (aTTP) treatment with additional evidence, and updated the guidance in congenital thrombotic thrombocytopenic purpura (cTTP)
With more than 5000 members across 100 countries, the ISTH is the leading thrombosis and hemostasis - related professional organization in the world

About ISTH

With more than 5000 members across 100 countries, the ISTH is the leading thrombosis and hemostasis–related professional organization in the world.3.

Why the ISTH Guidelines were developed

Diagnosing and treating TTP can be complicated.1

•The rarity of TTP—and its similar presentation to other TMAs—can make recognition a challenge

Diagnostic Challenges

○Rare disease, seen infrequently

○Signs and symptoms overlap with those of other TMAs and critical disorders with different treatment needs

○Acute onset and high mortality

○Rapid diagnosis is critical to minimize risk of mortality and long-term sequelae

○ADAMTS13 testing is not always available

•Management of TTP varies among healthcare professionals (HCPs)

•Treatment recommendations in TTP have evolved

ISTH created the guidelines as a comprehensive, uniform, international resource to inform the diagnosis and management of TTP1

The ISTH Guidelines can aid HCPs—both those with limited experience with TTP and those considered experts in TTP—in making a TTP diagnosis and following an appropriate treatment strategy.

These include1

• Emergency/critical care physicians

• Hematologists

• Nephrologists

• Neurologists

• Transfusion medicine specialists

• Hospitalists

• Policy makers

The ISTH has created the first evidence-based guidelines to support rapid TTP diagnosis and treatment.

After diagnosis and treatment, be on the lookout for refractory disease, relapse, and recurrence.

Monitoring TTP

Understand the long-term risks of TTP beyond the acute stages.

View long-term effects

ADAMTS13=a disintegrin and metalloproteinase with thrombospondin type 1 motif, 13.

References: 1. Zheng XL, Vesely SK, Cataland SR, et al. ISTH Guidelines for the diagnosis of thrombotic thrombocytopenic purpura. J Thromb Haemost. 2020;18(10):2486-2495. doi:10.1111/jth.15006 2. Zheng XL, Al-Housni Z, Cataland SR, et al. 2025 focused update of the 2020 ISTH guidelines for management of thrombotic thrombocytopenic purpura. J Thromb Haemost. 2025;23(11):3711-3732. doi:10.1016/j.jtha.2025.06.002 Epub 2025 Jun 17. 3. ISTH History. International Society on Thrombosis and Haemostasis website. http://www.ISTH.org/page/History