ANCA (anti-neutrophil cytoplasmic antibodies)

What is ANCA?

ANCA stands for Anti-neutrophil Cytoplasmic Antibodies. These are antibodies (a type of protein made by the immune system) that target specific proteins inside neutrophils, a type of white blood cell. The presence of ANCA in the blood may indicate certain autoimmune diseases, such as vasculitis.

Why test for ANCA?

Testing for ANCA is useful in diagnosing and monitoring autoimmune diseases, particularly vasculitis, a condition in which blood vessels become inflamed. It can help determine the specific form of the disease, guide treatment decisions, and monitor disease activity over time.

What does it indicate?

The presence of ANCA in the blood may indicate the presence of an autoimmune disease, especially vasculitis. There are various types of ANCA, the two most common being: PR3-ANCA and MPO-ANCA, which are associated with different forms of vasculitis.

What does a high ANCA level mean?

A high level of ANCA may indicate active vasculitis or another autoimmune disease. It means that an inflammatory process is ongoing, where the body's own cells are being attacked, potentially leading to damage to organs and tissues.

What does a low ANCA level mean?

A low or non-detectable ANCA level may indicate an absence of active vasculitis or that the disease is under control through treatment. It is important to know that ANCA levels can also be low in some individuals who still have an autoimmune disease, so test results must always be interpreted in conjunction with other clinical findings.

Myeloperoxidase (MPO, p-ANCA) and Proteinase 3 (PR3, c-ANCA)