Understanding ANCA Testing: What Are Antineutrophil Cytoplasmic Antibodies?

ANCA (Antineutrophil Cytoplasmic Antibodies) are the proteins our immune system makes that fallaciously damage the white blood cells known for fighting infection in the human body.

An ANCA test measures the number of autoantibodies in the blood; ANCA is also autoantibodies that target the proteins inside neutrophils. An ANCA test diagnoses specific types of vasculitis associated with swelling and inflammation in blood vessels. 

The two main types of ANCA-associated vasculitis (AAV) are granulomatosis with polyangiitis (GPA, formerly Wegener’s granulomatosis) and microscopic polyangiitis (MPA). 

Why is the ANCA test crucial?

ANCA test measures whether the ANCA antibody levels are elevated, as it may suggest the presence of these autoimmune vasculitic diseases. Any changes in ANCA levels may correlate with the progression or remission of vasculitis. 

The most severe implication that ANCA autoantibodies come up with is the blood vessel inflammation that may cause organ damage aneurysm. Aneurysm is the bulge in the outer layer of an artery wall that causes nausea, pain, dizziness, etc.   

Steps of ANCA test 

  1. Blood Collection: First, an expert healthcare professional will take a small sample of your blood, usually from a vein in your arm. The only risk attached to this step is a minor bruise or sting, which can be avoided if a trusted pathological lab like Aglius Diagnostics is relied upon.
  2. Laboratory Analysis: This blood sample is then sent to a laboratory where the doctors look for two types of ANCA: c-ANCA (cytoplasmic ANCA) and p-ANCA (perinuclear ANCA).
  3. Results: The results finally reveal whether or not these specific antibodies are present in your blood and quantify them. The levels in this report can indicate whether one is susceptible to ANCA-associated vasculitis, which involves inflammation of blood vessels.
  4. Clinical Interpretation: The doctors usually go through your symptoms, medical history, and other tests along with the ANCA test before coming to a full-proof conclusion of a diagnosis.
  5. Follow-Up: Depending on the results, your doctor may recommend further tests or procedures to understand your health condition better. If ANCA-associated vasculitis is suspected, the doctor can guide you to a specialist for subjective evaluation and other treatment.

The two standard modes of an ANCA test

Indirect Immunofluorescence (IIF)

Under this procedure, a blood sample is taken from the patient and mixed with a substrate containing neutrophils (white blood cells); after that, fluorescent dyed antibodies are added to identify, quantify, and differentiate between the C-ANCA and P-ANCA. The indirect Immunofluorescence IIF usually provides a binary result, i.e., the test result will either be positive or negative.

Enzyme-Linked Immunosorbent Assay (ELISA)

This immunological treatment uses enzymes and serums to detect the presence of specific antibodies in the blood sample. The ANCA antibodies bind to the antigens on the plate if they are present. The enzyme-labeled antibodies are added under the Enzyme-Linked Immunosorbent Assay (ELISA) test, which changes color, and the intensity of this color change as part of the reaction of the test surveys the concentration of ANCA antibodies present in the bloodstream. A higher concentration implies a more active autoimmune response. 

Indirect Immunofluorescence (IIF) and ELISA are complementary, and the choice of method depends on the laboratory’s preferences and the specific clinical scenario. Moreover, the results of these tests are interpreted parallelly with clinical findings and other diagnostic information to make a comprehensive assessment of the patient’s health.

How do you prepare for the ANCA test?

Before the test, you need to inform your doctor of whatever medications you consume daily so that, if required, the over-the-counter drugs that might influence the results are stopped. It is advisable to stay well hydrated before the blood collection, and in usual cases, no fasting is required; however, it is better to consult your doctor for your subjective case. 

After the ANCA test, doctors usually advise you to avoid heavy lifting that might strain the area from which your blood sample was collected. Any additional pressure on the region might invite unnecessary splitter-splatter of blood and bruises; in such a case, using a cotton ball to apply pressure. 

Results usually come within a week of the test being conducted. If the results are positive, the doctor will diagnose you with autoimmune vasculitis, in which case the treatment suitable to you will be started as soon as possible to avoid any lurking danger for your future. Besides the ANCA test, the doctor might even prescribe a biopsy (in which a sample tissue is examined) to confirm the presence of ANCA in your bloodstream.Don’t get confused about understanding the complicated terminology of IIF and Enzyme-Linked Immunosorbent Assay (ELISA); focus on your health, and after getting a check-up from the doctor, get your ANCA test done in a unique laboratory like Aglius Diagnostics, whose technicians experience will make your further ride of understanding the disorder smooth.

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