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Autoimmunity
Intrinsic factor antibodies
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Intrinsic factor is produced in the stomach and helps extract vitamin B12 from the foods we eat. Interference in its production or activity can reduce the absorption of vitamin B12. Intrinsic factor antibodies are produced by the immune system. Intrinsic factor is necessary to extract vitamin B12 from the food we eat. Without sufficient intrinsic factor available, vitamin B12 is unabsorbed and the body cannot produce enough red blood cells which leads to the autoimmune condition pernicious anaemia.
Special instructions
How to prepare for your test
Prepare for your Intrinsic Factor Antibodies Blood Test by following these instructions. Do not take vitamin B12 for two weeks prior to this test. If your B12 is prescribed ask your doctor whether to stop.
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FAQs
What can I learn from this test?
This test checks whether you have antibodies to intrinsic factor in your blood. These antibodies can lead to vitamin B12 deficiency and eventually pernicious anaemia, an autoimmune condition. If your intrinsic factor antibody levels are raised, you may need further tests to confirm your diagnosis, such as gastric parietal cell antibodies, vitamin B12 and MMA levels, and a full blood count to check for anaemia. Please note that titre levels are only provided for positive results.
What is pernicious anaemia?
Pernicious anaemia causes a deficiency in vitamin B12, an essential water-soluble vitamin found in virtually all meat products and certain algae, such as seaweed. It helps maintain healthy nerve and red blood cells and is required to make DNA, the genetic material in all cells. Symptoms of pernicious anaemia include fatigue, shortness of breath, brittle nails, pins and needles, and cognitive difficulties (brain fog). Symptoms of pernicious anaemia can become debilitating and cause lasting damage if not caught early enough. Pernicious anaemia can be treated by regular vitamin B12 injections.
What is intrinsic factor?
Intrinsic factor is a glycoprotein produced by the parietal cells in your stomach - and it is necessary to absorb vitamin B12 from the food you eat. Interference in the production or the activity of intrinsic factor can reduce vitamin B12 being absorbed in the small bowel, resulting in anaemia.
Limitations of the test
Read before you order:
Up to half of people with autoimmune gastritis or pernicious anaemia have a negative result, known as a false-negative result. This is especially true in the early stages of the disease where antibody levels are much lower. It’s also possible to receive a positive result even without having pernicious anaemia but this is less common. This test can’t detect the stage or severity of pernicious anaemia. It’s also not a diagnostic test – you will likely require further investigative tests if you receive a positive result.