Tests and diagnosis

By Mayo Clinic Staff

Besides asking you about your signs and symptoms, conducting a physical exam, and taking a medical history, your doctor may request several tests, including:

  • Blood tests. If your doctor suspects Wegener's granulomatosis, you'll have a blood test that can detect certain proteins (autoantibodies) in your blood called anti-neutrophil cytoplasmic autoantibodies (ANCA). These autoantibodies appear in the blood of most people with active Wegener's granulomatosis, but not all. The presence of these autoantibodies may mean you have Wegener's granulomatosis, but it isn't enough to confirm that you have the disease.

    Your blood test also can measure your erythrocyte sedimentation rate — commonly referred to as a sed rate. By measuring how quickly red blood cells fall to the bottom of a tube of your blood over a period of one hour, this test may indicate the level of inflammation in your body, but it doesn't definitively diagnose Wegener's. Generally, red blood cells fall faster when inflammation is present. Your sed rate will also be measured during treatment, to check the activity of your disease.

    Another blood test can check for anemia, which is common in people with this disease. A blood test for creatinine can check if your kidneys are properly filtering waste products from your blood.

  • Urine tests. These tests evaluate kidney function to determine whether the disease is affecting your kidneys.
  • Chest X-ray. This test shows cavities or masses in your lungs. However, it can't distinguish between Wegener's granulomatosis and other lung diseases.
  • Biopsy of affected tissue. The only sure way to confirm a diagnosis of Wegener's granulomatosis is to remove a small piece of tissue from an affected organ (biopsy) and examine it under a microscope. Your doctor may remove tissue from your nasal passages, airways or lungs to confirm or rule out the presence of both vasculitis and granulomas. Other areas for biopsy may include your skin or your kidneys. Some biopsies can be performed in an outpatient setting using a numbing medication (local anesthetic). Others, such as an open-lung biopsy, may require hospitalization.
Dec. 19, 2012