ANCA-c (anti-PR3)

The ANCA-c (anti-PR3) test, available at IntroLab Belgrade, is a specialized diagnostic test used primarily in rheumatology and nephrology to detect specific autoantibodies in the blood. These autoantibodies, known as cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA), are especially associated with granulomatosis with polyangiitis (formerly known as Wegener’s granulomatosis).

What are cANCA (anti-PR3)?

cANCA, or anti-PR3 antibodies, are a type of autoantibody—antibodies that the immune system mistakenly produces against the body’s own cells and tissues. These antibodies specifically target proteinase 3 (PR3), an enzyme found in neutrophil leukocytes, a type of white blood cell. The presence of these antibodies can indicate certain autoimmune diseases.

When and who should get tested for cANCA (anti-PR3)?

Testing for cANCA (anti-PR3) antibodies is important for individuals suspected of having granulomatosis with polyangiitis or other vasculitic diseases. The test is also used to monitor the progression of these diseases and the effectiveness of their treatment.

This test is recommended if there are symptoms suggestive of vasculitic disease, including:

• Unexplained weight loss
• Persistent fatigue
• Fever
• Pain
• Joint swelling
• Nosebleeds
• Red spots on the skin
• Coughing, with or without blood
• Shortness of breath
• Chest pain

How is the ANCA-c (anti-PR3) test performed?

The test is conducted using a blood sample. Blood is usually drawn from a vein in the arm, and then it is analyzed in the laboratory to detect the presence of cANCA (anti-PR3) antibodies.

How are the results interpreted?

The results are interpreted based on standardized reference values for this test. Elevated levels of ANCA-c (anti-PR3) suggest a potential presence of autoimmune diseases, while lower levels typically do not require further attention unless they contradict the patient’s clinical presentation.

Specifics and subtypes of ANCA antibodies

There are several types of ANCA antibodies, including cANCA (anti-PR3) and pANCA (anti-MPO). Each type is associated with specific indications and diseases. The presence of these antibodies is not definitive proof of disease. A negative test does not rule out the disease, and a positive test does not confirm it. Test results should be interpreted in the context of the patient’s symptoms, medical history, and other diagnostic tests.