Thrombotic thrombocytopenic purpura (TTP) is a rare disorder usually caused by autoantibodies to ADAMTS13, a protease that regulates von Willebrand factor (VWF) multimer size. Severe ADAMTS13 deficiency leads to accumulation of ultra-large VWF, VWF-platelet aggregates, and occlusive microvascular platelet thrombi leading to microangiopathic hemolytic anemia, thrombocytopenia, and organ ischemia and dysfunction. Improved clinical recognition, early treatment, and ADAMTS13 laboratory testing to support the diagnosis have decreased the mortality rate, which is 90% in untreated patients. This presentation will use a case-based format to review ADAMTS13 testing modalities including activity, antibody, and genetic testing. Clinical and laboratory features that can lead to diagnostic difficulty, and the impact of treatment on testing, including new therapies, will be explored.
Learning Objectives - after participation of this activity, participants will be able to:
1. Use a case-based format to review the landscape of ADAMTS13 laboratory testing
2. Highlight patient and laboratory characteristics that can lead to difficulties diagnosing TTP
3. Discuss TTP therapies and impact of these therapies on test results