Do I need to eat gluten before this test?

Yes - this is critical. You must eat gluten regularly (equivalent to 1-2 slices of bread daily) for at least 2-4 weeks before testing. Going gluten-free before testing will cause false-negative results because antibody levels drop quickly without gluten exposure.

What if my TTG is negative but I still react to gluten?

A negative TTG does not rule out non-celiac gluten sensitivity (NCGS), which does not produce these antibodies. If TTG is negative and you were eating gluten, celiac is unlikely, but you may still have gluten sensitivity or other digestive conditions like IBS.

Why test both IgA and IgG?

About 2-3% of celiac patients have IgA deficiency, which causes false-negative TTG IgA results. Testing TTG IgG catches these cases. If your TTG IgA is negative, your doctor may also check your total IgA level.

What happens if my test is positive?

A positive TTG typically leads to referral to a gastroenterologist for endoscopy with small intestine biopsy - the gold standard for celiac diagnosis. Some newer guidelines allow diagnosis without biopsy if antibody levels are very high (>10x normal) with classic symptoms.

Can I have celiac disease without digestive symptoms?

Yes. Silent or atypical celiac disease is common. Some people have only fatigue, anemia, bone loss, or neurological symptoms. First-degree relatives should be screened even without symptoms due to their elevated risk.

🛡️ Autoimmune

TTG IgA & IgG Blood Test - Celiac Disease Screening

Name: TTG IgA & IgG Blood Test - Celiac Disease Screening
Brand: Justlabs
SKU: 11073
Price: 45 USD
Availability: InStock

TTG Antibodies

The most accurate blood test for celiac disease screening. Measures antibodies your body produces in response to gluten if you have celiac disease.

The Tissue Transglutaminase (TTG) antibody test is the recommended first-line screening test for celiac disease. It measures two types of antibodies:

TTG IgA is the primary marker and is highly sensitive and specific for celiac disease in people with normal IgA levels.

TTG IgG is included because approximately 2-3% of celiac patients have IgA deficiency, which would cause a false-negative IgA result.

Celiac disease is an autoimmune condition where gluten triggers the immune system to attack the small intestine, leading to malabsorption, nutritional deficiencies, and various symptoms.

Important: You must be eating gluten regularly for at least 2-4 weeks before testing. A gluten-free diet will cause antibody levels to drop, potentially causing false-negative results.

Price

$45

Results

3-5 business days

Lab Network

Quest

Fasting

Not Required

What's Measured

tTG IgA

tTG IgG

What This Test Measures

This panel measures two antibodies:

TTG IgA: Primary celiac marker (normal: <4 U/mL, varies by lab)
- Weak positive: 4-10 U/mL
- Positive: >10 U/mL
TTG IgG: Secondary marker for IgA-deficient patients
- Important when TTG IgA is negative but symptoms persist

Higher antibody levels generally correlate with more intestinal damage, though levels can vary.

Who Should Consider This Test

Anyone with digestive symptoms that may indicate celiac disease (chronic diarrhea, bloating, abdominal pain, weight loss). Also recommended for those with unexplained iron deficiency, vitamin D deficiency, osteoporosis, or fatigue. First-degree relatives of celiac patients (10x higher risk), people with other autoimmune conditions (Type 1 diabetes, thyroid disease), and those with dermatitis herpetiformis (celiac skin rash).

Health Insights

Conditions Screened

Celiac diseaseGluten sensitivity assessmentDermatitis herpetiformis

Related Symptoms

Chronic diarrheaBloatingAbdominal painUnexplained weight lossFatigueIron deficiencyBrain fogJoint painSkin rashNumbness or tingling

When to Get Tested

No fasting required. Critical: You must be eating gluten regularly for at least 2-4 weeks before testing. If you have already gone gluten-free, you will need to do a "gluten challenge" - eating gluten daily for 2-4 weeks before testing. Without gluten exposure, antibodies will decline and cause false-negative results.

Understanding Your Results

Negative (TTG IgA <4 U/mL): Celiac disease unlikely. If symptoms persist and you have eaten gluten regularly, consider total IgA level testing to rule out IgA deficiency.

Weak Positive (TTG IgA 4-10 U/mL): Borderline result - may need repeat testing or additional markers (EMA, DGP antibodies).

Positive (TTG IgA >10 U/mL): Highly suggestive of celiac disease. Confirmation typically requires endoscopy with intestinal biopsy, though some guidelines allow diagnosis based on very high antibody levels (>10x normal) with symptoms.

Note: A positive TTG does not diagnose celiac disease alone - it indicates the need for further evaluation.

What to Expect

After placing your order, you'll receive an email from Rupa Health (our lab order partner) within 24 business hours to sign a consent form and schedule your blood draw at a Quest Diagnostics location.

The blood draw typically takes just a few minutes. Results are usually available within 3-5 business days and will appear in your secure Justlabs dashboard.

Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.