Diagnosis

Your doctor will ask you about your signs and symptoms, conduct a physical exam, and take your medical history.

Lab tests

Blood tests can check 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.
• Anti-neutrophil cytoplasmic antibodies, which appear in the blood of most people who have active granulomatosis with polyangiitis.
• Anemia, which is common in people with this disease.
• Signs that your kidneys aren’t properly filtering waste products from your blood.

Urine tests can reveal whether your urine contains red blood cells or has too much protein, which might indicate that the disease is affecting your kidneys.

Imaging tests

Chest X-rays, CT or MRI can help determine which blood vessels and organs are affected. They can also help your doctor monitor whether you're responding to treatment.

Biopsy

This is a surgical procedure in which your doctor removes a small sample of tissue from the affected area of your body. A biopsy can confirm a diagnosis of granulomatosis with polyangiitis.