Contributed by -Healthians Team

What is the ANCA test?

Antineutrophil cytoplasmic antibodies (ANCA) are autoantibodies created by the immune system that mistakenly target the specific protein neutrophil which is a type of white blood cell. This can lead to a disorder called systemic vasculitis. This disease is associated with the inflammation of blood vessels and leads to organ failure because damaged blood vessels can’t carry enough blood to all the organs from the heart. 

Two common types of ANCA autoantibodies perinuclear (p-ANCA) and cytoplasmic (c-ANCA) target proteins myeloperoxidase (MPO) and protein 3 (PR3) inside white blood cells. ANCA test is performed to measure the number of auto-antibodies in the blood. This test can show whether the person has these antibodies in their body or not so that the healthcare provider can diagnose the health problems.

Who should get tested?

The doctor may recommend an ANCA test if there are any kind of symptoms such as:

  • Fever
  • Muscle aches
  • Weight loss
  • Improper kidney and lung functions

These symptoms can lead to vascular autoimmune disorder. These symptoms also affect specific organs of the body including the eyes, ears, lungs, sinuses, kidneys, and nervous system. 

Why is the ANCA test needed?

An ANCA test is used to detect autoimmune disorders like systemic vasculitis which causes damage to the blood vessels. Ulcerative colitis is an autoimmune disease that is associated with the inflammation of the lining of the colon and develops tiny open sores, or ulcers. This disease can be difficult to distinguish from Crohn’s disease (CD) that can affect any part of the digestive tract. These two diseases are commonly known as inflammatory bowel disease.

Signs and symptoms of inflammatory bowel disease include:

  • Abdominal pain and cramps
  • Diarrhoea
  • Rectal bleeding
  • Fever
  • Fatigue
  • Joint, skin, bone, or organ-related problems

ANCA test may be ordered with some other tests to distinguish between ulcerative colitis (UC) from Crohn’s disease (CD).

What does the ANCA test result mean?

A positive test result means the person is affected with autoimmune vasculitis. This test helps to find the p-ANCA or c-ANCA antibodies that help the doctor to find out the type of vasculitis. A negative test result means there are no symptoms of autoimmune vasculitis and the doctor may perform some other tests. 

In a positive test result, a doctor may take any additional steps or order some other tests to confirm the diagnosis. Additionally, a titer test is performed to determine the presence of antibodies. The healthcare practitioner considers the signs and symptoms in addition to the results to detect the disease.

How is the ANCA test done?

To perform this test, the healthcare professional will take a sample of the person’s blood. First, they clean the spot with an antiseptic liquid and tie the band on the upper arm to find the vein.  Then a needle is inserted into the vein and a blood sample is collected. After collecting the blood sample, it is sent to the lab for testing. There is no preparation needed for this test. If you’re taking any medicines or have any preexisting medical conditions, then you have to inform your doctor because these conditions can influence the test results.

Take the ANCA test now