InstalabCeliac Disease Panel
Should you take a Celiac Disease Panel test?
This test is most useful if any of these apply to you.
2 Biomarkers Included
About Celiac Disease Panel
About one in every hundred people has celiac disease, an autoimmune condition where eating gluten triggers the immune system to attack the lining of the small intestine. The damage unfolds slowly, often over years, and most people who have it do not know. A large U.S. study found that for every person diagnosed with celiac disease, several more remained undiagnosed despite carrying the same antibodies and intestinal damage. Left unchecked, the condition can quietly cause iron deficiency, bone loss, nerve problems, and an increased risk of certain cancers.
This two-test panel is the guideline-recommended first step for finding out whether gluten is causing your body harm. One test looks for the immune attack itself. The other makes sure the first test can actually work. Without both, you risk a false sense of security.
What This Panel Reveals
The panel answers two linked questions. First, is your immune system producing antibodies that attack your own tissue in response to gluten? Second, is your body capable of making the type of antibody being measured? The answers only mean something when read together.
The primary screening marker is tTG IgA, short for tissue transglutaminase immunoglobulin A. When you eat gluten and have celiac disease, your immune system produces IgA (immunoglobulin A, a class of antibody concentrated in the gut lining) directed against an enzyme called tissue transglutaminase. This enzyme is involved in processing gluten fragments, and the immune system mistakenly targets it. A positive tTG IgA result is a strong signal that celiac disease is present.
The second test, total IgA, measures the overall level of immunoglobulin A in your blood. This is not a celiac marker itself. It exists in the panel for one reason: to make sure the tTG IgA result is trustworthy. About 2 to 3 percent of people with celiac disease have a condition called selective IgA deficiency, meaning their bodies produce very little IgA overall. In those people, tTG IgA will come back normal even if celiac disease is raging, because there is not enough IgA in the blood to generate a positive signal.
How to Read Your Results Together
The value of this panel lies in reading both results as a pair. A single test in isolation can mislead you. Here are the patterns that matter.
| tTG IgA | Total IgA | What It Means |
|---|---|---|
| Positive (elevated) | Normal | Strong likelihood of celiac disease. The antibody screen is reliable and flagged an immune response to gluten. Follow up with a gastroenterologist, who will likely recommend an upper endoscopy (a scope procedure where a thin, flexible tube examines the digestive tract) with small intestinal biopsy to confirm. |
| Negative (normal) | Normal | Celiac disease is unlikely at this time. Your IgA level is adequate, so the negative tTG IgA result is trustworthy. If symptoms persist or you have a first degree relative with celiac disease, consider retesting in 1 to 2 years. |
| Negative (normal) | Low (below range) | The tTG IgA result cannot be trusted. Your body does not produce enough IgA for the test to work. You need IgG-based celiac testing (such as deamidated gliadin peptide IgG or tTG IgG) to get a reliable answer. |
| Weakly positive (borderline) | Normal | Possible early or mild celiac disease, but false positives can occur at low tTG IgA levels. Retest in 3 to 6 months. If still elevated, pursue endoscopy. |
The most dangerous scenario is the third row: a normal tTG IgA paired with low total IgA. Without the total IgA check, you would walk away thinking you do not have celiac disease when you might. This is the entire reason the panel includes both tests.
Who Should Get Screened
The American College of Gastroenterology (ACG) recommends blood antibody testing for celiac disease in several groups. Anyone with chronic diarrhea, unexplained weight loss, or iron deficiency anemia should be tested. So should people with bloating, abdominal pain, or other persistent digestive symptoms that lack a clear explanation.
First degree relatives of someone with confirmed celiac disease carry a substantially higher risk. Studies estimate that 5 to 15 percent of parents, siblings, and children of celiac patients will also have the condition. If you fall into this group, screening makes sense even if you feel perfectly well, because celiac disease can be silent for years while intestinal damage accumulates.
People with type 1 diabetes, autoimmune thyroid disease, unexplained liver enzyme elevations, or early onset osteoporosis also warrant screening. These conditions overlap with celiac disease at rates well above the general population.
When Results Can Be Misleading
Both tests assume you are currently eating gluten. If you have already removed gluten from your diet before testing, tTG IgA levels may have dropped back to normal, producing a false negative. The ACG recommends eating gluten for several weeks before testing to ensure antibodies are detectable. A common guideline is the equivalent of about two slices of bread daily for at least two to six weeks before testing.
Certain conditions can produce a mildly positive tTG IgA without celiac disease. Chronic liver disease, inflammatory bowel disease, and heart failure have all been associated with false positive results at low tTG IgA levels. The higher the tTG IgA level, the more likely it reflects true celiac disease. Levels more than ten times the upper limit of normal are so strongly associated with celiac disease that some guidelines allow a diagnosis without biopsy in children.
Total IgA levels can be affected by medications that suppress the immune system. If you are taking immunosuppressants, mention this when reviewing results with a clinician.
Tracking Over Time
If you have been diagnosed with celiac disease and started a gluten free diet, this panel becomes a monitoring tool. tTG IgA levels should decline steadily after you eliminate gluten, typically normalizing within 6 to 24 months. Persistently elevated tTG IgA after a year on a strict gluten free diet suggests ongoing gluten exposure, whether intentional or accidental.
For people who tested negative but remain symptomatic or have a family history of celiac disease, repeating the panel every one to two years is reasonable. Celiac disease can develop at any age. A negative result today does not guarantee a negative result in five years, especially if you carry the genetic predisposition (the HLA-DQ2 or HLA-DQ8 gene variants present in virtually all celiac patients).
Serial testing also helps track dietary compliance once diagnosed. A tTG IgA that was falling but suddenly rises again is a clear signal that gluten has reentered the diet, even if you are not aware of the source.
What to Do with Your Results
If tTG IgA is elevated and total IgA is normal, your next step is a referral to a gastroenterologist for an upper endoscopy with small intestinal biopsy. During this procedure, a doctor guides a thin, flexible tube with a camera into the small intestine and takes tiny tissue samples. Biopsy remains the standard for confirming celiac disease in adults, because it shows the characteristic damage to the intestinal villi (the tiny finger-like projections that absorb nutrients). Do not start a gluten free diet before the biopsy, as removing gluten can heal the intestine and make the biopsy inconclusive.
If total IgA is low, ask for IgG-based celiac tests. Deamidated gliadin peptide IgG (DGP IgG) and tTG IgG are the most commonly used alternatives. These bypass the IgA blind spot entirely.
If everything comes back normal and you still suspect gluten is a problem, consider HLA-DQ2/DQ8 genetic testing. A negative genetic test essentially rules out celiac disease for life, since the condition cannot develop without these gene variants. A positive genetic test does not confirm celiac disease (about 30 to 40 percent of the general population carries these genes), but it tells you the door remains open and future screening is worthwhile.