What is a celiac disease blood test?
A celiac disease blood test looks for signs of celiac disease in a sample of your blood. Celiac disease is a chronic (long-term) digestive and immune disorder that damages your small intestine. The damage may prevent your body from absorbing vitamins, minerals, and other nutrients from the food you eat. This can lead to malnutrition, anemia and other serious health problems.
Celiac disease is a type of autoimmune disease. That means that your own immune system attacks healthy cells in your body. Normally, your immune system makes proteins called antibodies to fight germs. With celiac disease, problems start if you eat foods that have a protein called gluten. Your immune system "thinks" the gluten proteins are germs, so it makes antibodies that attack the lining of your small intestine.
Gluten is found in wheat, barley, rye, and some other grains. It's also found in certain toothpastes, lipsticks, medicines, and other products. A celiac disease test looks for antibodies to gluten in your blood sample.
Other names: celiac disease antibody test, anti-tissue transglutaminase antibody (anti-tTG), deaminated gliadin peptide antibodies, anti-endometrial antibodies
Why do I need a celiac disease blood test?
You may need a celiac disease test if you have symptoms of celiac disease. Symptoms can vary a lot, and they may come and go. Children tend to have more digestive problems than adults.
The digestive symptoms of celiac disease include:
- Bloating (feeling fullness or swelling in your belly)
- Chronic (long-term) diarrhea or greasy, bulky, unusually bad-smelling stool (poop)
- Lactose intolerance because of damage to the small intestine
- Nausea and vomiting
- Pain in the abdomen (belly)
- Weight loss in adults, or not enough weight gain in children
Some people with celiac disease have symptoms that affect other parts of the body, such as:
- Depression and anxiety
- Irritability (in children)
- Itchy rash with blisters (mainly in adults)
Other conditions such as gluten sensitivity and wheat allergies may cause symptoms that are much like celiac disease. But these are different conditions. They don't damage the small intestine, and they are diagnosed with different tests.
You may need a celiac test if you have a high risk for having the disease even if you don't have symptoms. Celiac disease is a genetic disorder. That means it's passed down from parents to children through genes. You are more likely to have celiac disease if you:
- Have a parent, sibling or child who has the disease
- Have another autoimmune disorder, such as type 1 diabetes
Most people who have genes for celiac disease don't get the disease. But screening may still be important. That's because you could have intestinal damage from celiac disease even if you don't seem to notice any symptoms. This is called "silent celiac disease." Talk with your health care provider to see if you should be tested.
What happens during a celiac disease blood test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Will I need to do anything to prepare for the test?
If the test is being used to diagnose celiac disease, you'll need to continue to eat foods with gluten for a few weeks before testing. Your health care provider will give you specific instructions about how to prepare for the test.
If the test is being used to monitor celiac disease, you don't need any special preparations.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
What do the results mean?
There are different types of celiac disease antibodies, so your celiac blood test results may include information on more than one type of antibody. Your results may also include other blood tests you had to look for signs of celiac disease. Your provider can explain what all your test results say about your health.
In general, results from a celiac disease blood test may be:
- Negative. This means that celiac disease antibodies weren't found in your blood. So, you probably don't have celiac disease.
- Positive. This mean that celiac disease antibodies were found in your blood. So, you're likely to have celiac disease. To confirm the diagnosis, you will need more tests to look for damage in your intestines.
- Uncertain, indeterminate, or inconclusive. These terms all mean that it's unclear whether you have celiac disease.
Your provider may order other tests to confirm that you have celiac disease and/or to see how much damage the disease may have caused. These tests may include:
- A biopsy to examine a tissue sample from your small intestine or your skin if you have a rash that could be from celiac disease. An endoscopy is used to take a sample of tissue from your small intestine.
- Capsule endoscopy to look at your small intestine. For this test, you swallow a tiny camera in a capsule. As it passes through your small intestine, it records pictures. The camera leaves your body during a bowel movement (poop).
- Genetic testing to see if you have a gene linked to celiac disease
- Tests for other health problems that celiac disease may cause such as anemia, osteoporosis, or a lack of certain vitamins.
Learn more about laboratory tests, reference ranges, and understanding results.
Is there anything else I need to know about a celiac disease test?
Most people with celiac disease will feel better if they avoid foods and products with gluten. Your provider may refer you to a registered dietician (a nutrition expert) who can help you learn how to eat a healthy diet without gluten. Eating a gluten-free diet usually helps heals damage in the small intestine and prevents more damage. Many people see symptoms improve within days to weeks of starting the diet.
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