How is the disease diagnosed?

Wegener's granulomatosis has symptoms similar to a number of other disorders, which may make it difficult to diagnose. However, for the most effective and successful treatment, early diagnosis is critical.

It is the combination of symptoms, results of physical examinations, laboratory tests, X-rays, and sometimes a biopsy (sample) of affected tissue (skin, nose, sinus, lung, or kidney) that together prove the diagnosis of Wegener's granulomatosis. Following treatment, these factors are also critical in judging whether the disease is active or in remission.

A positive blood test for antineutrophil cytoplasmic antibodies (ANCA) can support a suspected diagnosis of the disease. However, this blood test does not by itself prove the diagnosis of Wegener's granulomatosis or determine disease activity.

Other tests that influence a doctor's judgment of disease activity include:

• Measures of anemia (red blood cell count)
• Sedimentation rate (the speed in which blood cells settle in a vertical glass tube) Urinalysis
• Chest or sinus X-rays

Sometimes the lungs may become abnormal even though there are no symptoms such as cough or shortness of breath. Therefore, it is important to periodically have lung X-rays if you are diagnosed with Wegener's granulomatosis - even if you don't have any symptoms of lung disease.