A tissue biopsy is the gold standard test for diagnosis of vasculitis. It involves taking a tissue sample from a blood vessel or affected organ and examining it for signs of inflammation or damage. This is the only way to be sure of a diagnosis of vasculitis; however, it is invasive, so a combination of laboratory and non-laboratory tests, in addition to a review of signs and symptoms, medical history, and a physical exam, can be used to help in decision-making. For example, tests can help pinpoint an organ involved on which to perform a biopsy to confirm or exclude a diagnosis of vasculitis. Several of these tests are also used to monitor treatment.
- Complete Blood Count (CBC) – this test is used to look for complications of vasculitis and its treatment. It evaluates the patient's red blood cells and hemoglobin for anemia and checks the white blood cell count, which can be increased in infection and reduced with some treatments. Higher than normal numbers of white blood cells are seen with some types of vasculitis, such as Churg-Strauss Syndrome.
- Erythrocyte sedimentation rate (ESR) – this test shows the presence of inflammation in the body and can be increased with some types of vasculitis, such as microscopic polyangitis and Wegener's Granulomatosis.
- C-reactive protein test (CRP) - this test also detects inflammation in the body.
- Creatinine – this test assesses kidney function to determine if the vasculitis is affecting the kidneys.
- Liver panel – these tests assess liver function to determine if the vasculitis is affecting the liver.
- Urinalysis – this test looks for presence of protein and red blood cells in the urine, which can indicate inflammation in the kidney as can occur with some types of vasculitis.
- Anti-neutrophil cytoplasmic antibody (ANCA) – this test is a useful marker for primary systemic vasculitis conditions, such as Wegener's Granulomatosis and Microscopic Polyangitis.
- Complement – part of the inflammatory response often reduced with vasculitis when immune complex-related conditions such as this are present.
- Radiological imaging – chest x-ray, EKG, echocardiography, CT scan, MRI can be used to help determine if large arteries are affected.
- Lung function tests – to determine if airflow is restricted when vasculitis is affecting the lungs.
- Nerve conduction studies or nerve biopsy may be useful if there are symptoms of numbness or tingling.
- Angiography, an x-ray examination of the blood vessels after dye has been injected into the bloodstream, can be useful in some types of vasculitis.
For more on imaging studies, see the web site Radiologyinfo.org.