Anti-tissue Transglutaminase Antibody
Does this test have other names?
IgA anti-tissue transglutaminase, IgA Anti-tTG, celiac disease testing
What is this test?
This test is used to see if you have celiac disease. It is also used to see how well
people with the condition are doing. It is one of several blood tests that may be
used to help diagnose celiac disease.
Tissue transglutaminase is an enzyme that fixes damage in your body. People with celiac
disease often make antibodies that attack this enzyme. These are called anti-tissue
transglutaminase antibodies. A blood test that shows higher levels of anti-tissue
transglutaminase antibodies can help your healthcare provider figure out if you have
Why do I need this test?
If you have celiac disease, you are allergic to gluten. Gluten is the protein found
in wheat, rye, and barley. Celiac disease is an autoimmune disorder. This means your
body attacks itself. With celiac disease, your body attacks the lining of the small
bowel, making it less able to absorb nutrients. The sensitivity to gluten can also
cause pain in the abdomen, low blood count (anemia), tiredness, muscle and joint pain,
gas, diarrhea, vomiting, weight loss, and malnutrition.
What other tests might I have along with this test?
If your healthcare provider thinks you have celiac disease, he or she may order several
other blood tests. These may look for generalized inflammation (C reactive protein
or erythrocyte sedimentation rate) or poor absorption of nutrients (iron deficiency,
low cell counts, or unabsorbed fat in stool).
Your provider may also take a tissue sample (biopsy) from your small bowel to confirm
the blood tests' findings. The biopsy is important to confirm a diagnosis of celiac
disease. It should be done when possible. The biopsy is done using a tubelike device
(endoscope) put down your throat and into the small intestine. Your provider uses
it to get the sample without doing surgery.
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
Keep in mind that no one test can say for sure that you have celiac disease. Your
healthcare provider will use other things to help confirm the diagnosis.
The higher the levels of anti-tissue transglutaminase antibodies in your blood, the
more likely it is that you have it or a related disorder. Younger children are an
exception to this rule. A test may come back negative even if the child has celiac
disease. But other tests can give a proper diagnosis.
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in
your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
What might affect my test results?
This test is considered the best and most specific blood test for diagnosing celiac
disease. But 2% to 3% of people with celiac disease don't have enough IgA antibodies,
the substance the test looks for. This can lead to a false-negative result.
In addition, the test is not as accurate for young children. Other tests may need
to be done to confirm celiac disease.
How do I get ready for this test?
If the test is to diagnose celiac disease, it is best to have it before you stop eating
gluten. This is because the lack of gluten could give a negative test result even
if you have celiac disease. If the test is to see how well you are doing with celiac
disease, you don't need to get ready for the test. Be sure your healthcare provider
knows about all medicines, herbs, vitamins, and supplements you are taking. This includes
medicines that don't need a prescription and any illicit drugs you may use.