Diagnosis of Thrombotic Thrombocytopenic Purpura
Recommendations
- Step 1: Acquire a plasma sample for ADAMTS13 testing (eg, ADAMTS13 activity and inhibitors or anti‐ADAMTS13 IgG) before an initiation of TPE or use of any blood product.
- Step 2: Start TPE and corticosteroids without waiting for the results of ADAMTS13 testing.
- Step 3: Consider early administration of caplacizumab before receiving plasma ADAMTS13 activity results.
- Step 4: When the result of plasma ADAMTS13 activity is available, continue caplacizumab if ADAMTS13 activity is less than 10 IU/dL (or <10% of normal) (a positive result) or stop caplacizumab and consider other diagnoses if ADAMTS13 activity is >20 IU/dL (or >20% of normal) (a negative result).
- Step 5: For patients with plasma ADAMTS13 activity less than 10 IU/dL (or <10% of normal) (a positive result), also consider adding rituximab as early as possible, as a majority of these adult patients (>95%) have autoantibodies against ADAMTS13.
- Step 1: Acquire a plasma sample for ADAMTS13 testing (eg, ADAMTS13 activity and inhibitor or anti‐ADAMTS13 IgG) before an initiation of TPE or use of any blood product.
- Step 2: Consider starting TPE and corticosteroids, depending on the clinician's judgment and assessment of the individual patient.
- Step 3: Do not start caplacizumab until the result of plasma ADAMTS13 activity becomes available.
- Step 4: When the result of plasma ADAMTS13 activity testing is available, consider adding caplacizumab and rituximab if ADAMTS13 activity is less than 10 IU/dL (or <10% of normal) with inhibitors or an elevated level of anti‐ADAMTS13 IgG (a positive test result), but do not start caplacizumab and consider other diagnoses if ADAMTS13 activity is greater than 20 IU/dL (or >20% of normal) (a negative result).
Recommendation Grading
Overview
Title
Diagnosis of Thrombotic Thrombocytopenic Purpura
Authoring Organization
International Society on Thrombosis and Haemostasis
Publication Month/Year
July 1, 2020
Last Updated Month/Year
October 15, 2024
Supplemental Implementation Tools
Document Type
Guideline
External Publication Status
Published
Country of Publication
US
Document Objectives
The evidence-based guidelines of the International Society on Thrombosisand Haemostasis (ISTH) are intended to support patients, clinicians, and other healthcare professionals in their decisions about the initial diagnosis and management ofacute Thrombotic thrombocytopenic purpura (TTP).
Target Patient Population
Adult patients with a suspected Thrombotic thrombocytopenic purpura (TTP)
Target Provider Population
Primary care physicians, emergency orcritical care physicians, hematologists, nephrologists, neurologists, pathologists or transfusion medicine specialists, surgeons, obstetricians and gynecologists, as well as hospitalists
Inclusion Criteria
Male, Female, Adult
Health Care Settings
Ambulatory, Hospital, Long term care
Intended Users
Nurse, nurse practitioner, physician, physician assistant
Scope
Diagnosis, Management
Diseases/Conditions (MeSH)
D003933 - Diagnosis, D011697 - Purpura, Thrombotic Thrombocytopenic
Keywords
diagnosis, thrombosis, Guidelines, TTP, ADAMTS13