Celiac Testing: What You Need to Know Before You Get Screened

When you suspect celiac disease, an autoimmune disorder triggered by gluten that damages the small intestine. Also known as gluten intolerance, it affects about 1 in 100 people, but up to 80% go undiagnosed. If you’ve had unexplained fatigue, bloating, diarrhea, or even brain fog after eating bread or pasta, it’s not just "sensitive stomach"—it could be your immune system attacking your own gut lining.

Celiac testing starts with a simple tTG-IgA blood test, a screening tool that detects antibodies your body makes in response to gluten. But here’s the catch: you have to be eating gluten for this to work. If you’ve already cut out wheat and dairy because you "feel better," the test will likely come back negative—even if you have celiac. That’s why so many people get misdiagnosed. A negative blood test doesn’t rule it out. That’s where endoscopy with biopsy, the gold standard for confirming celiac disease by checking for intestinal damage comes in. It’s the only way to see if your villi are flattened, which is the real sign of celiac.

Many people confuse celiac with non-celiac gluten sensitivity, a real condition where gluten causes symptoms but doesn’t trigger autoimmune damage. The difference matters because one requires strict, lifelong avoidance, and the other might not. There’s no blood test for gluten sensitivity—it’s diagnosed by ruling everything else out. And if you’re testing for celiac, don’t skip checking for vitamin deficiencies, common in untreated celiac due to poor nutrient absorption. Iron, B12, D, and calcium levels often tell the real story before symptoms even show up.

What you’ll find in the posts below are real, practical insights from people who’ve been through the testing maze. Some discovered celiac after years of misdiagnosis. Others learned why their gluten-free diet didn’t fix everything. You’ll see how insurance coverage plays into testing, what doctors often miss, and how to ask the right questions so you don’t get handed a false negative. This isn’t theory—it’s what works when you’re tired of guessing what’s making you sick.