As with most types of vasculitis there is no one test that will give the diagnosis. The diagnosis is usually made because the doctor recognises the typical collection of symptoms and clinical signs. Blood tests for inflammation (ESR - erythrocyte sedimentation rate; CRP - C-reactive protein; plasma viscosity) will usually be high indicating inflammation but these are not specific and can be raised in any type of vasculitis, many infections and other types of inflammatory disease. If the temporal arteries are involved (located at the sides of the forehead over the temples) then a biopsy may be performed. If the biopsy shows inflammation this will help to confirm the diagnosis. Unfortunately a biopsy without inflammation does not exclude the diagnosis. Sometimes an ultra sound scan of the arteries is used instead of a biopsy.