Diagnosis of Cutaneous Vasculitis Exclusion of clinically evident causes of systemic vasculitis Routine tests (eg, complete blood count, erythrocyte sedimentation rate, urinalysis, serum creatinine, chest x-ray) Biopsy Tests to identify the type and etiology of vasculitis (eg, cryoglobulins, antineutrophil cytoplasmic antibodies, hepatitis B and C antibodies, C3 and C4 complement levels, rheumatoid factor, blood cultures, protein electrophoresis) A diagnosis of vasculitis limited to the skin requires a complete history and physical examination.