Anti Tissue Transglutaminase IgG

OVERVIEW

What is a celiac disease?

It is an autoimmune disorder where body produces inappropriate immune response against gluten i.e., a protein found in wheat, & related dietary proteins in barley and rye. Celiac disease & few other gluten-sensitive diseases can be diagnosed & monitored via antibody tests which look for autoantibodies in the blood. Various antibodies are measured for its amount found in blood that help in differential diagnosis of celiac disease. These antibody tests include tTG IgA, IgA, tTG IgG, & DGP antibodies IgA/IgG.

What is anti-tissue transglutaminase IgG lab test?

This test is used for quantitative determination i.e., measures number of antibodies released against tissue transglutaminase (tTG) an enzyme which is normally present in intestine. In autoimmune disorder when body mistakenly takes nonthreatening substance as threatening and starts producing immune response, it makes two antibodies namely IgA and IgG (immunoglobulin G) to attack tTG. IgG antibodies are released after several weeks of infection but stays for long time in the body providing immunity.

Why is anti-tissue transglutaminase IgG lab test done?

The test is done:

• As it is primary test used for screening for celiac disease
• This blood test is very sensitive and specific for celiac disease and tTG IgA class is single test preferred by American College of Gastroenterology for detection of celiac disease in children over the age of 2.
• This test is also very useful for monitoring the condition and evaluating the effectiveness of the treatment.
• It is also screening test for dermatitis herpetiformis (autoimmune skin condition)
• IgG antibody is less specific for celiac disease, but it tends to be useful in diagnosing autoimmune conditions in patients who are IgA antibody deficient.
• Used in celiac disease suspected patients, symptomatic patients, atypical symptomatic patients, & those at increased risk of disease

• Firstly, a blood sample is taken by inserting needle in vein in arm.
• The sample is then collected in air-tight vial/syringe or test tube & sent to the laboratory
• The technician isolates plasma or serum from the blood sample, then performs anti-tTG IgG test. And it looks for antibodies against tissue transglutaminase for celiac disease.

1. Is fasting required while going for celiac panel blood test?

If for diagnosis, the continue eating food with gluten in it for some period prior to testing. If for monitoring, then no preparation is needed

2. How long should you eat gluten before celiac blood test?

Eating a little gluten each day like having a slice of regular bread or two for a week or ten days, is helpful for producing antibodies which can be diagnosed by the doctor later in the test

3. In celiac disease, is IgA high or low?

There are only about 3% people with celiac disease and IgA deficiency both. So, if serum IgA tTG result comes negative and there is strong suspicion of disease, then serum total IgA levels are measured

4. What is a celiac attack like?

People sensitive to gluten/celiac disease have symptoms like bloating, gas, diarrhea (loose motions), anemia (low hemoglobin), & growth issues

5. How long does antibodies against gluten stay in blood?

Depends upon which antibody test is done. In case of tTG, there half-life is of 6 months in the blood.

INTERPRATATION OF THE RESULTS:

The ranges interpret the following:

• <6.0 U/mL: Negative; indicates reduced likelihood of having celiac disease
• 6.0- 9.0 U/mL: Weakly positive
• >9.0 U/mL: Positive; indicates that celiac disease is present and is consistent with diagnosis of celiac disease

You get tested when you suspect having celiac disease, if patients are showing symptoms of celiac disease, patients with atypical symptoms, & in people with increased risk of celiac disease. It helps in evaluation of treatment response with gluten-free diet. It is preferred in individuals with IgA deficiency.