Antinuclear Antibodies Test

Posted October 2, 2022 by Anusha ‐ 4 min read

An ANA test is a blood test that looks for antinuclear antibodies (ANAs) in your child’s blood. If your child tests positive for ANAs, it may mean they have an autoimmune disorder. An autoimmune disorder causes your child’s immune system to attack their own cells by mistake.

What is an ANA test?

  • An antinuclear antibody (ANA) test looks for antinuclear antibodies in your child’s blood.

  • If your child tests positive for ANAs, it may mean they have an autoimmune disease.

  • An autoimmune disease causes your child’s immune system to attack their own cells, tissues and organs by mistake.

What are antinuclear antibodies?

  • Antibodies are proteins made by white blood cells in your child’s immune system.

  • Antibodies help defend against invaders (such as viruses and bacteria) that cause disease or infection.

  • Sometimes antibodies mistakenly attack your child’s own cells.

  • These antibodies are called autoantibodies.

  • An antinuclear antibody is an autoantibody that targets the center (nucleus) of a cell.

  • The nucleus contains DNA, which tells the cell what to do.

  • If there are enough antinuclear antibodies present, your child’s immune system may start to attack its own body.

  • Large amounts of ANAs in your child’s blood may be a sign of an autoimmune disease.

  • But not everyone with elevated ANA levels has an autoimmune disease.

  • Up to 30% of healthy people have detectable levels of ANAs.

  • They’re also present in people with viral infections and in people using certain medications.

What is an ANA test used for?

Autoimmune diseases that can cause a positive ANA result include:

  • Systemic lupus erythematosus (SLE): SLE (lupus) is an inflammatory disease. It causes joint pain, fever, weakness, fatigue, skin rashes and organ damage.

  • Scleroderma: Scleroderma is a rare disease that causes abnormal thickening and hardening of your child’s skin and tissues. It can also affect your child’s gastrointestinal tract, lungs, kidneys, heart, blood vessels, muscles and joints.

  • Polymyositis: Polymyositis is a disease of your child’s muscles that causes inflammation and weakness. It usually affects the muscles closest to your child’s trunk.

  • Dermatomyositis: Dermatomyositis occurs when people have disease features of polymyositis and also skin involvement such as a scaly rash, swelling and purple spots.

  • Mixed connective tissue disease (MCTD): MCTD shares features with SLE, scleroderma and polymyositis. Usually, the symptoms of these diseases don’t occur at the same time. Rather, they occur one after the other over a long period of time.

  • Juvenile onset idiopathic arthritis (JIA): JIA is a type of arthritis that may affect the joints in a variety of ways in your child’s body. Their hands, wrists, knees and other joints may be affected. It may also affect other parts of your child’s body, including their skin, eyes, lungs, heart and blood.

  • Sjögren’s syndrome: Sjögren’s syndrome is a condition that reduces the amount of moisture produced by the glands in your child’s eyes and mouth. Your child’s immune system damages the tear system in their eyes and the salivary glands in their mouth.

How does an ANA test work?

  • An ANA test measures the level of antinuclear antibodies in a blood serum sample.

  • The most widely used method is called indirect immunofluorescence assay (IFA).

  • Another name for this method is fluorescent antinuclear antibody (FANA) test.

  • With an ANA screen with IFA, a pathologist will add your child’s serum sample to a microscope slide.

  • They’ll add an antibody containing a fluorescent dye to the sample.

  • The fluorescent antibody attaches to the cells in the sample.

  • When a pathologist views the slide under a special microscope, any present ANAs will appear as fluorescent cells.

What should my child expect during an ANA test?

  • An ANA test is a blood test. Your child’s healthcare provider will collect a small amount of blood in their office or a laboratory.

  • Your child’s healthcare provider will look for a good vein to use on your child’s arm.

  • Once they find a usable vein, they may tie an elastic band around your child’s upper arm or ask your child to make a fist.

  • They’ll clean the site and then insert a small needle into the vein.

  • Your child’s healthcare provider will draw a small amount of blood into a test tube or vial.

  • When the tube is full, they’ll remove the elastic band from around your child’s arm and withdraw the needle from their arm.

  • Your child may feel a slight sting as the needle goes in or out.

  • They may also feel a slight throbbing at the site where the blood was drawn.

What should my child expect after an ANA test?

  • After the ANA test, your child’s healthcare provider may use gauze or a cotton ball to apply slight pressure to the site where the blood was drawn.

  • This helps reduce bleeding, swelling and bruising.

  • They’ll apply a clean, dry bandage to the site.

  • The entire process usually takes less than five minutes.

  • Then, your child’s healthcare provider will send the sample to a laboratory for testing.

What are the risks and side effects of an ANA test?

  • There’s very little risk to having a blood test.

  • Your child may experience minor discomfort or bruising at the site where the blood was drawn.

  • But any pain or bruising should quickly subside.

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