Diagnostic algorithm for patients suspected of VITT. Recommended diagnostic algorithm for patient presenting with signs and symptoms of VITT. *Symptoms may include: headache, visual disturbances, fever, hemiparesis, abdominal pain, dyspnea, and limb swelling/pain. ^§Anti-PF4 ELISA testing plus serotonin-release assay for confirmation of VITT diagnosis; if studies are negative, but clinical suspicion high, avoid heparin products. ^†IVIG as sole therapy for thrombosis should be considered only if anticoagulation contraindicated.