What Is a Blood Test?
A blood test is when a sample of blood
is taken from the body to be tested in a lab. Doctors order blood tests to check things
such as the levels of glucose,
hemoglobin, or white blood cells. This can help them find problems like a disease
or medical condition. Sometimes, blood tests can help them see how well an organ (such
as the liver or kidneys)
is working.
What Is a Tissue Transglutaminase IgA (tTG-IgA) Test?
A tissue transglutaminase IgA (tTg-IgA) test is used to help doctors diagnose celiac disease. Celiac
disease is an autoimmune disorder in which the immune
system mistakenly thinks that gluten — a protein in wheat, barley, rye,
and oats — is a foreign invader. The immune system makes antibodies that attack
an enzyme in the intestines called tissue transglutaminase (tTG).
Why Are tTG-IgA Tests Done?
A tTG-IgA test may be done if a child has symptoms of celiac disease, such as poor
growth, belly pain, constipation,
vomiting, diarrhea, or rashes.
A tTg-IgA test also might be done if a child has a condition that makes celiac
disease more likely (such as type
1 diabetes), thyroid
disease, or a family member with celiac disease.
How Should We Prepare for a tTG-IgA Test?
For the test to be accurate, your child should be on a gluten-containing diet until
the test is done.
Your child should be able to eat and drink normally unless also getting other tests
that require fasting beforehand. Tell your doctor about any medicines your child takes
because some drugs might affect the test results.
Wearing a T-shirt or short-sleeved shirt for the test can make things easier for
your child, and you also can bring along a toy or book as a distraction.
How Is a tTG-IgA Test Done?
Most blood tests take a small amount of blood from a vein. To do that, a health
professional will:
- clean the skin
- put an elastic band (tourniquet) above the area to get the veins to swell with
blood
- insert a needle into a vein (usually in the arm inside of the elbow or on the
back of the hand)
- pull the blood sample into a vial or syringe
- take off the elastic band and remove the needle from the vein
Collecting a sample of blood is only temporarily uncomfortable and can feel like
a quick pinprick.
