Diagnosis and Tests for Celiac Disease

The celiac diagnosis has one golden rule: get tested BEFORE stopping gluten. Every test depends on the immune system still reacting to gluten; a few weeks off wheat can turn a true case falsely negative and cost you a clear answer.

Step 1: The blood test

• tTG-IgA (tissue transglutaminase antibody): the standard first test - a simple blood draw available at most Indian labs
• Total IgA measured alongside: some people are IgA-deficient, which hides the tTG-IgA result; they need an IgG-based test instead
• EMA and DGP tests: supporting antibody tests for special situations and young children

A strongly positive tTG-IgA in a symptomatic person is very likely celiac disease.

Step 2: The biopsy (confirmation)

An endoscopy through the mouth takes tiny samples from the small intestine - a 15-minute day procedure, not an operation. The pathologist grades the damage (Marsh 1-3). Biopsy confirmation remains the standard, especially before committing a child or an uncertain adult to a lifelong diet.

Step 3: Gene testing (to rule out, not rule in)

HLA-DQ2/DQ8 testing: a negative result excludes celiac disease with near-certainty - useful when the picture is confusing or someone already stopped gluten before testing. A positive result only means risk exists; a third of healthy people carry these genes.

Tests for the damage done

• Iron studies, vitamin B12, folate, vitamin D, calcium, zinc - the deficiency panel that also tracks recovery
• Bone density scan (DEXA) in adults at diagnosis or with fracture history
• Thyroid and diabetes screening, since autoimmune companions travel together

Special situations

• Already gluten-free without testing: a supervised gluten challenge (weeks of daily gluten) before testing - done only with a doctor
• Children: same pathway; many pediatric cases now confirmed on very high blood markers alone per specialist judgment

One-line summary

Blood tTG-IgA first, endoscopic biopsy to confirm, gene test to exclude - all while still eating gluten; stopping wheat early is the commonest way the diagnosis gets lost.