The nervous system and heart occasionally may be affected. Fever and night sweats also may occur. However, fever also may signal an underlying infection, often of the upper respiratory tract. To treat people with Wegener's granulomatosis most effectively, doctors must diagnose the disease early in its course. There are no blood tests that a doctor can use to diagnose Wegener's granulomatosis, but blood tests are important to rule out other causes of illness and to determine which organ sites may be affected.
Most blood tests are nonspecific and can only suggest that a person has an inflammatory process.
X-ray results can be very helpful in diagnosing Wegener's granulomatosis. People with lung involvement will have abnormal chest x-rays, which may show one or many fluffy infiltrates, solid nodules, or cavities. Although a positive ANCA test is useful in supporting a suspected diagnosis of Wegener's granulomatosis, in most instances it is not used by itself to make a diagnosis of this disorder. The ANCA test may be negative in some patients with active Wegener's granulomatosis. A biopsy is very important both to confirm the presence of Wegener's granulomatosis and also to assure the absence of other disorders that may have similar signs and symptoms.