In the beginning, basic blood tests to check your blood count, kidney function, liver tests, and urine tests help guide in the diagnosis. When you see your rheumatologist, they might order further specific testing. Since the symptoms of vasculitis are so variable depending on the type of vasculitis, the testing also depend on the suspected type of vasculitis. If you are suspected to have small vessel vasculitis, there is a blood test called ANCA, which is a very specific marker for this disease. Your doctors will also order markers of inflammation, such as sedimentation rate and C-reactive protein or CRP. You may also require biopsy of the involved organ, such as kidneys, lungs, or the skin to make the accurate diagnosis. In case of suspected large vessel vasculitis, imaging studies such as MRIs or CT are essential to make this diagnosis. The imaging study will show signs of inflammation within the blood vessels, helping make the diagnosis.