Antinuclear Antibodies

The immune system is responsible for safeguarding the body against the threat of germs and viruses. The antibodies are the fighting force generated by the immune system to fight any foreign materials that enter the body. However, antinuclear antibodies and some other antibodies may mistakenly identify the body's own tissues and cells as foreign materials and start attacking them.

What Are Antinuclear Antibodies?

Antibodies are essentially proteins which are tasked with the duty of recognizing infections and fighting them off. Antibodies are usually designed for targeting foreign materials such as viruses and bacteria and helping the immune system in destroying them.

However, antibodies can sometimes be made against healthy proteins in the body by mistake. Such antibodies can launch an autoimmune response against the body's tissues and cells. Antibodies which start targeting normal proteins in the nucleus of the cells are referred to as antinuclear antibodies or ANAs for short, which could also be called Antinuclear Factor or ANF.

ANAs have many subtypes, like anti-sp100 antibodies, anti-histone antibodies, anti-Scl-70 antibodies, anti-La antibodies and anti-Ro antibodies. Every antibody subtype attaches to a different protein complex present in the nucleus. ANAs are present in a number of disorders such as infection, cancer and autoimmunity. This is the reason why ANAs are used for diagnosing autoimmune disorders like Dermatomyositis, Polymyositis, mixed connective tissues disease, scleroderma, systemic lupus erythematosus, etc.

Why Is an Antinuclear Antibodies Test Needed?

The presence of ANAs in the body is normal; however, if they are present in a large amount, then it can be an indication that either you are suffering from an autoimmune disease or are more vulnerable to it than others. If the body starts receiving signals to attack its own cells, then the chances of an autoimmune disease like mixed connective tissue disease, scleroderma and lupus occurring increase a great deal.

An ANA test is a diagnostic test performed to measure the amount of antibodies present in blood. It is used as a confirmation test to diagnose various autoimmune diseases. The test is very simple and requires only a small sample of blood that can be collected at a clinic or lab.

How to Perform an ANA Test

Performing an ANA test is not that difficult. Here is a detailed account of how this test is performed in clinics.

  • The first step is the drawing of the blood from a vein from the back of the hand or the inside of the elbow. An antiseptic or a germ-killing medication is applied on the site to get it cleaned and an elastic band is wrapped around the upper portion of the arm to pressurize the area and get the blood in the vein below to swell up.
  • After this, the health care provider inserts a hypodermic needle into the selected vein very gently to draw the blood. After this, the elastic band is taken off from the arm and the puncture site is covered with an adhesive bandage to stop bleeding.
  • A lancet might be used in young children or infants. In such cases, a pipette, which is a small glass tube, is used for collecting the blood. Blood can also be collected on a test strip or slide too. Then cover it with bandage to stop any bleeding.

Note: It is normal to feel a slight amount of pain or a sensation of being stung or pricked upon insertion of the needle. Some throbbing might remain afterwards.

What Do the Results of an ANA Test Means?

An ANA test measures the pattern and amount of antibodies present in blood that are causing an autoimmune reaction or are working against your body. The test is considered to be positive if the blood contains more antinuclear antibodies than normal. In case the test turns out to be positive, the lab is going to immediately perform other tests to identify its cause. These tests will try to find out the type of antibodies that are present in an abnormally high amount in the blood.

A number of reasons can lead to a positive antinuclear antibodies test:

1. Viral Infections

2. Medications used for treating tuberculosis (TB), heart disease and high blood pressure.

3. Autoimmune connective tissue diseases

  • Raynaud's syndrome
  • Polymyositis
  • Juvenile idiopathic arthritis
  • Sjogren's syndrome
  • Scleroderma
  • SLE (Systemic Lupus Erythematosus). Patients of SLE always have a positive ANA test but people with positive ANA tests don't always have SLE.
  • Rheumatoid arthritis. Most patients with rheumatoid arthritis have positive ANA tests.
  • Hashimoto’s Thyroiditis (Thyroid disease)
  • Hepatitis (Liver disease)
  • Hemolytic Anemia and Idiopathic Thrombocytopenia (ITP) (Blood Cell diseases)
  • Addison's disease


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