ANCA (Anti-Neutrophil Cytoplasmic Antibodies)

The Anti-Neutrophil Cytoplasmic Antibody (ANCA) test measures the presence of specific antibodies that target proteins in the cytoplasm of neutrophils (a type of white blood cell). These antibodies are primarily associated with autoimmune diseases, where the body's immune system mistakenly attacks its own tissues. The ANCA test is used to help diagnose and monitor vasculitis, which is the inflammation of blood vessels. It is particularly useful in diagnosing granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and other forms of small vessel vasculitis.

Who should get this test done?

Individuals who may benefit from the ANCA test include:

• Those with symptoms of vasculitis, such as unexplained fatigue, muscle and joint pain, skin rashes, fever, and unexplained organ damage (especially the kidneys, lungs, or skin)
• People with suspected granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), or other autoimmune diseases affecting blood vessels
• Individuals who have been diagnosed with vasculitis or are being treated for it and need monitoring for disease activity or remission
• People with recurrent or unexplained respiratory or kidney symptoms, especially if they show signs of vessel inflammation or damage
• Individuals with a family history of autoimmune diseases or vasculitis

More Information

The ANCA test plays a crucial role in diagnosing autoimmune diseases, particularly vasculitis, which can cause significant damage to various organs. Vasculitis can lead to inflammation of the blood vessels, restricting blood flow and causing organ damage. ANCA antibodies are often seen in patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), two forms of small vessel vasculitis.

There are two main types of ANCA:

• c-ANCA (cytoplasmic ANCA), which is most often associated with granulomatosis with polyangiitis (GPA).
• p-ANCA (perinuclear ANCA), which is more commonly linked with microscopic polyangiitis (MPA) and other forms of vasculitis.

The presence of these antibodies in the blood, particularly when combined with symptoms and other tests, can help confirm a diagnosis of vasculitis and guide treatment decisions. However, it’s important to note that while ANCA can be a useful diagnostic tool, not all patients with vasculitis have detectable levels of ANCA, and other tests may be required to make a final diagnosis.