Autoantibody Testing
Autoantibody testing checks a sample of your blood for autoantibodies, proteins made by the immune system .
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). Other names: 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
Why is this test ordered? 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.
Clinical Interpretation
Your results may depend on the type of autoantibody test you had. But generally, your results will be either positive or negative. A negative (normal) result means that you have little or no autoantibodies in your blood. But that doesn't rule out an autoimmune disease. People with rheumatoid arthritis, for example, may have little to no RF in their blood. If you have symptoms of an autoimmune disease, but your results are normal, your provider may order more tests to make a diagnosis. A positive (abnormal) result means that some amount of autoantibodies were found in your blood. This doesn't necessarily mean that you have an autoimmune disease. Some healthy people have autoantibodies in their blood. To make a diagnosis, your provider will consider other test results along with your symptoms and medical history. Some results may give a number for how many autoantibodies were found. This is called a titer. If a titer is provided, your results will also have a reference range. A reference range is a set of numbers that form the high and low ends of the range of results that's considered normal. So, a titer value that is higher than the reference range may be a sign of an autoimmune disease. The results for autoantibody panels, such as ANA and ENA tests, might also go into detail for each of the autoantibodies tested. This means you could have positive results for some autoantibody tests and negative results for others. Because autoantibody test results can mean so many different things, it's important to talk to your provider about what your results mean for you . Learn more about laboratory tests, reference ranges, and understanding results .
Clinical Protocol & Patient Advice
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You don't need any special preparations for autoantibody testing.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.