The gut needs time to mount an antibody response that can be measured in the blood, which is why we recommend 12 weeks of eating gluten. If you experience symptoms immediately, it’s likely that the gut itself has quickly become damaged. In these cases, you and your medical professional could consider a shorter gluten challenge (~week) and then have a biopsy; we’ve learned that evidence in the gut can be seen within about a week of eating gluten-containing foods. Diagnosis is not an exact science, each person responds differently to the presence of gluten in the small intestine and the amount of time it has been there. Be sure to work with your medical professional to adjust your diet, if needed, during your gluten challenge. December, 2012