Autoantibody Testing

Autoantibody testing checks a sample of your blood for autoantibodies, proteins made by the immune system. Normally, your immune system makes proteins called antibodies to attack germs that could make you sick. Autoantibodies, however, do not attack germs.

They instead attack your own healthy tissue and organs, believing them to be foreign substances. This can lead to the development of an autoimmune disease. There are more than 80 types of autoimmune diseases, and they can affect almost any part of your body.

Your immune system makes autoantibodies by mistake. Researchers aren't entirely sure why, though your body is more likely to make them if you: Have a family history of autoimmune diseases.; Have a viral or bacterial infection, especially if it's chronic (long-term). This can cause your immune system to be overactive, which can lead to the production of autoantibodies.; Are exposed to certain environmental toxins.; There are many different types of autoantibodies, and they can affect your body in different ways.

Some affect only specific organs and/or parts of your body. These are called organ-specific antibodies. For example: Thyroid antibodies, such as anti-TPO, only affect your thyroid.; Smooth muscle antibodies (SMAs) attack smooth muscle, usually in the liver.; Islet cell autoantibodies attack cells in your pancreas.; Other antibodies, however, affect multiple organs and can cause a variety of symptoms.

These are called systemic antibodies. This type can include: Antinuclear Antibody (ANA).; Antineutrophil Cytoplasmic Antibodies (ANCA).; Anti-Double Stranded DNA (anti-dsDNA).; Antihistone Antibodies.; Rheumatoid Factor (RF).;

Why this test is done

You may need autoantibody testing if you have symptoms commonly associated with some autoimmune diseases. The symptoms of an autoimmune disease depend on the part of your body that's affected. These can include:

• Fever.
• Fatigue.
• Joint symptoms, including pain and swelling.
• Muscle pain or weakness.
• Swollen glands.
• Abdominal (belly) pain and/or cramps.
• Rashes that can't be explained.
• Unexpected weight loss or gain.
• Palpitations (racing or pounding heart).
• Anxiety and depression.
• Seizures.

Other illnesses can, however, cause the same symptoms. Symptoms for many autoimmune conditions may also come and go.

You may also need an autoantibody test if you've been diagnosed with an autoimmune disease, and your provider wants to monitor your condition. For example, a provider may order an islet autoantibodies test if they want to monitor your Type 1 diabetes, which is a type of organ-specific autoimmune disease. You may need an RF test if you have symptoms of rheumatoid arthritis.

These may include:

• Joint pain or stiffness when moving. This is usually worse in the morning or after inactivity. RA usually affects both joints. If one of your hands or knees is affected, so is the other.
• Joint tenderness, redness, and warmth.
• Joint swelling that may make activities hard. These could include things such as combing your hair, buttoning your clothes, or bending your knees.
• Fatigue, fever, and a loss of appetite.
• Hard bumps (rheumatoid nodules) under your skin near the joints.

You may also need an RF test if your health care provider wants to check for other conditions that can cause high RF levels. These may include:

• Other autoimmune disorders, including:
• Sjögren syndrome.
• Lupus.
• Scleroderma.
• Juvenile idiopathic arthritis in children and teens.
• Chronic infections, including:
• Hepatitis C (liver).
• Tuberculosis (mostly affects the lungs).
• Endocarditis (heart).
• Certain types of cancer, including leukemia.

People with rheumatoid arthritis often develop anemia, so if you have anemia, your provider may want to give you an RF test. It is rare to get tested for high RF levels if you don't have symptoms of any of the above conditions.

How to prepare

You don't need any special preparations for autoantibody testing. You don't need any special preparations for an RF test.

Sample type

Blood

Other names for this test

antibody serology test, antinuclear antibody (ANA) test, extractable nuclear antigen (ENA) test, anti-dsDNA test, rheumatoid factor (RF) test, antineutrophil cytoplasmic antibodies (ANCA) test, smooth muscle antibody (SMA) test, thyroid antibody test, RF Blood Test