Up to 85% of Americans with celiac disease don’t know they have it. That’s the figure at the center of a new report from Celiac.com, and it points to a diagnosis gap that researchers have been tracking for decades without making enough progress on closing. Millions of people are living with an active autoimmune disease, accumulating intestinal damage, and never getting an explanation for their symptoms.
That number hit close to home for me. My son has celiac disease. I know firsthand how long and circuitous the path to diagnosis can be, and how much easier the outcome is when someone finally asks the right question and orders the right test. The families who never get that moment — that’s what this report is really about.
What This Means for You
Celiac disease affects roughly 1% of the global population, or about 3 million Americans. But population screening studies consistently find that diagnosed patients represent only a fraction of that group — somewhere between 15% and 20%. Everyone else either hasn’t been tested, has been misdiagnosed with something else, or has symptoms mild enough that no one has connected the dots.
This matters because celiac disease causes intestinal damage whether or not you feel obviously sick. The small intestine’s lining — covered in tiny fingerlike projections called villi that absorb nutrients — flattens over time when gluten is present. That damage accumulates silently in many people. Undiagnosed celiac is linked to higher rates of osteoporosis, anemia, infertility, certain cancers, and other autoimmune conditions. Diagnosis doesn’t just explain symptoms — it prevents long-term harm.
The other piece that makes this frustrating: celiac disease can look like dozens of other conditions. Fatigue, joint pain, brain fog, skin rashes, depression, anemia, and neurological symptoms are all documented manifestations of celiac — and none of them say “intestinal disease” to most doctors on first glance. People with these presentations often spend years cycling through other diagnoses before someone considers celiac. That diagnostic delay has historically averaged six to ten years in the United States.
For families raising children with celiac, the underdiagnosis picture adds a layer of concern. First-degree relatives of a diagnosed celiac patient — parents, siblings, children — have roughly a 10% chance of also having the disease. That’s ten times the rate in the general population. If your child has celiac, their siblings and parents deserve testing, even without obvious symptoms. Most guidelines recommend it; not enough providers mention it.
Key Takeaways
- An estimated 85% of Americans with celiac disease have not been diagnosed — that’s approximately 2.5 million people.
- Celiac disease causes intestinal damage even when symptoms are subtle or absent.
- The average time from first symptoms to diagnosis has historically been six to ten years in the United States.
- First-degree relatives of celiac patients have a roughly 10% chance of also having the disease and should be tested.
- A simple blood test — the tTG-IgA panel — is the standard first step in celiac screening; ask your provider about it if celiac has never been ruled out.
The Science
Want to understand how researchers arrived at the 85% figure — and why it’s so hard to close that gap? The details below walk through the evidence. Every technical term is defined when it first appears.
Where the 85% Figure Comes From
The underdiagnosis estimate comes from comparing two numbers: the seroprevalence rate (the share of the population that tests positive for celiac antibodies in blood screenings) versus the diagnosed prevalence rate (the share who have an actual celiac diagnosis on record).
The landmark data source for U.S. estimates is the National Health and Nutrition Examination Survey, or NHANES — a CDC program that tests representative samples of the American population. NHANES blood screenings have consistently found celiac antibodies in about 1% of participants. But when researchers look at how many of those people actually carry a celiac diagnosis, the number drops to roughly 0.2%. That gap — 1% versus 0.2% — is where the 80-85% underdiagnosis estimate comes from.
We’ve covered the global picture in depth before: the Global Prevalence of Celiac Disease meta-analysis found similar patterns across dozens of countries, with diagnosed rates consistently trailing seroprevalence estimates by a wide margin.
Why the Diagnosis Gap Persists
Several forces maintain the underdiagnosis problem despite decades of awareness campaigns.
First, celiac disease presents differently in different people. The “classic” presentation — chronic diarrhea, bloating, and significant weight loss — is actually less common than it once was thought to be. Many patients today present with what clinicians call atypical or extraintestinal symptoms: fatigue, iron-deficiency anemia, peripheral neuropathy (nerve pain or numbness), dermatitis herpetiformis (a blistering skin rash), and mood disorders. None of these symptoms shout “celiac” on a standard workup, so providers often pursue other explanations first.
Second, a substantial portion of celiac patients are asymptomatic or minimally symptomatic — meaning they feel generally fine. Their intestines are still damaged by gluten exposure, but they have no compelling reason to seek testing. This group will never find their way to a diagnosis through symptoms alone; only active population screening or testing of at-risk groups would catch them.
Third, physician awareness gaps remain a real problem. Celiac disease is still sometimes taught as a childhood condition, or as rare, or as something that only presents with GI distress. Providers who hold those beliefs are less likely to order the tTG-IgA test (tissue transglutaminase IgA antibody — the standard blood screening tool for celiac disease) when patients present with ambiguous or non-GI complaints.
The Genetics of Risk
Celiac disease requires two things: the right genetic background and gluten exposure. About 95% of celiac patients carry one of two HLA (human leukocyte antigen) gene variants — specifically HLA-DQ2 or HLA-DQ8. These genes help shape how the immune system responds to gluten fragments called gliadin peptides. In people with DQ2 or DQ8, those fragments trigger an immune response that attacks the intestinal lining.
Importantly, roughly 30-40% of the general population carries DQ2 or DQ8 — but only about 1-3% of that group ever develops celiac disease. The genetics are necessary but not sufficient. Environmental factors, including the timing of gluten introduction, gut microbiome composition, and prior infections, all appear to influence whether someone with the genetic risk actually develops the condition. This makes population-wide genetic screening alone an impractical diagnostic tool — it would flag tens of millions of people who will never develop the disease.
A 2024 analysis we covered earlier looked specifically at HLA-DQ allotypes in adults screened for celiac disease through the HUNT study and found that historical misdiagnosis was common — pointing again to the structural weaknesses in how the healthcare system currently identifies celiac patients.
What Would Actually Close the Gap
Researchers have proposed several approaches: targeted screening of high-risk groups (first-degree relatives, people with type 1 diabetes, thyroid disease, or Down syndrome), better primary care training on atypical presentations, and broader use of the tTG-IgA panel for patients with unexplained anemia or fatigue. Some countries in Europe have experimented with pediatric mass screening programs, and the data are promising — though no broad consensus exists on routine population screening in the United States.
For now, the most practical lever available to families is awareness: knowing that celiac disease can hide behind unexpected symptoms, that first-degree relatives are at elevated risk, and that a blood test is a low-barrier first step. None of that requires a policy change. It just requires asking the question.
Related Coverage
- How Common Is Celiac Disease? What the Major Prevalence Studies Tell Us
- Global Prevalence of Celiac Disease and Clinical Characteristics in the General Population: A Systematic Review and Meta-analysis
- HLA-DQ Allotypes in Adults Screened for Celiac Disease Reveal Historical Misdiagnosis — Results from the HUNT Study
References
- Celiac.com. “Could Up to 85% of Americans With Celiac Disease Still Be Undiagnosed?” Published August 18, 2026. Source
- Rubio-Tapia A, et al. “The Prevalence of Celiac Disease in the United States.” American Journal of Gastroenterology. 2012.
- Singh P, et al. “Global Prevalence of Celiac Disease: Systematic Review and Meta-analysis.” Clinical Gastroenterology and Hepatology. 2018.
- Fasano A, et al. “Prevalence of Celiac Disease in At-Risk and Not-At-Risk Groups in the United States.” Archives of Internal Medicine. 2003.
Always consult a qualified healthcare provider before pursuing celiac testing or making changes to your or your family’s diet.