Twenty-nine patients with clinically defined Takayasu arteritis and 26 healthy control volunteers were recruited by INSSYS investigators from their clinical practices. Patients with Takayasu arteritis were divided into those with clear-cut clinically active or inactive disease based on Birmingham Vasculitis Activity Scores. Multiple serological tests were performed including ESR, C-reactive protein, tissue factor, von Willebrand factor, thrombomodulin, tissue plasminogen activator, ICAM-1, VCAM-1, E-selectin and PECAM-1. No test was reliably able to distinguish between healthy volunteers and patients with active Takayasu arteritis. At present there is no known serological test which can consistently supplant vascular histopathology in determining the activity of Takayasu arteritis.