Your doctor will ask you about your signs and symptoms, conduct a physical exam, and take your medical history. He or she may also have you undergo diagnostic tests and procedures, such as the following:
Blood tests. These tests can be used to look for signs of inflammation, such as a high level of C-reactive protein or a high erythrocyte sedimentation rate — commonly referred to as a sed rate. A blood test that looks for certain antibodies — the anti-neutrophil cytoplasmic antibodies test — may be helpful because these substances appear in the blood of most people who have active granulomatosis with polyangiitis.
Another blood test can check for anemia, which is common in people with this disease. A blood test for creatinine can check whether your kidneys are properly filtering waste products from your blood.
- Urine tests. These tests may reveal whether your urine contains red blood cells or has too much protein, which may indicate the disease is affecting your kidneys.
- Chest imaging. Imaging tests can help determine what blood vessels and organs are affected. They can also help your doctor monitor whether you're responding to treatment. You may be asked to undergo chest X-rays, computerized tomography (CT) or magnetic resonance imaging (MRI).
- Biopsy. This is a surgical procedure in which your doctor removes a small sample of tissue from the affected area of your body. It's the only way to confirm a diagnosis of granulomatosis with polyangiitis.