Clinical care pathway for investigating suspected vaccine-induced immune thrombotic thrombocytopenia (VITT). All patients presenting to a health care setting with symptoms suspicious of thrombosis within 4 to 28 days after ChAdOx1 nCoV-19 vaccination were sent to the laboratory for a stat complete blood count (CBC). The patient was directed to the emergency department if VITT was suspected because of thrombocytopenia (platelets <150 000/mm³) or if thrombosis symptoms warranted further investigations. Stat CBC, blood film, INR, aPTT, d-dimer, fibrinogen, and COVID-19 testing were done. Patients who had normal results were managed according to standard practice. If any of these results were abnormal or if the emergency physician had a high suspicion of thrombosis, VITT was considered possible. This prompted hematology consultation and collection of blood samples for PF4-ELISA testing and imaging for thrombosis. Starting empiric treatment with IVIG and nonheparin anticoagulant was discussed with hematology and stroke neurology if cerebral venous thrombosis was confirmed or suspected. Samples were sent to the McMaster Platelet Immunology Laboratory in Hamilton, ON, Canada, for confirmation of platelet-activating PF4 antibodies. aPTT, activated partial thromboplastin time; ELISA, enzyme-linked immunosorbent assay; INR, international normalized ratio; PF4, platelet factor 4.