Inclusion Criteria:  1.Acute episode TTP:  Adult male or female patient ≥18 years of age at the time of signing the consent form, with a confirmed diagnosis of TTP (initial or relapse) based on ADAMTS13 <10% 2. Known diagnosis of TTP: Adult male or female patient ≥ 18 years of age at time of signing the consent form, with a historical confirmed diagnosis of TTP (based on ADAMTS13 at initial presentation <10%) 3. Healthy control: Non-blood relative / friend / carer of patients under the care of Haematology clinics at the Royal Liverpool University hospital or other participating centres.  Exclusion Criteria:  Acute episode of TTP:  Participants less than 18 years old at the time of signing the consent form Patient with ADAMTS13 greater than 10% Patient with cancer or transplant associated MAHA will not be included Patient (or NOK, where patient does not have capacity) not wishing to consent to trial  Known diagnosis of TTP:  Participants less than 18 years old at the time of signing the consent form Patient with ADAMTS13 greater than 10% Patient with cancer or transplant associated MAHA will not be included Patient (or NOK, where patient does not have capacity) not wishing to consent to trial  For healthy control:  Participants less than 18 years old at the time of signing the consent form Participant not wishing to consent to trial Any personal or family history of thrombotic microangiopathy