The full answer
Diagnosis typically has two steps
Celiac disease diagnosis usually starts with a blood test that checks for specific antibodies produced when the immune system reacts to gluten. If that test is positive, the standard next step is an endoscopy with a small intestine biopsy to confirm the characteristic villi damage — blood tests alone are considered a strong indicator, but a biopsy remains the most definitive confirmation.
Why testing order matters
Both tests only work reliably while gluten is still part of the diet, which is why it’s important not to start a gluten-free diet before testing. For the full clinical process, see the NIDDK’s diagnosis guide.
Important context
Individual symptoms, reactions, medical histories, food products, and local labeling rules can vary. Community experiences are not medical evidence.
For personal medical decisions, diagnosis, testing, or treatment, consult a qualified healthcare professional.