The blood test used to screen for celiac disease can create a false sense of security when the patient has type 1 diabetes, new research shows. Published in Postgraduate Medicine, a 12-year study of children with type 1 diabetes found that celiac antibody levels can rise, fall, and rise again over time — meaning a negative result at one annual checkup does not mean the disease is absent. More alarming: some children with biopsy-confirmed celiac disease never produced antibody levels high enough to trigger a biopsy under standard diagnostic guidelines.
What This Means for You
Children with type 1 diabetes (T1D) are already at significantly higher risk for celiac disease than the general population — estimates consistently put the rate at 5–10%, compared to roughly 1% overall. That shared genetic risk means most pediatric endocrinology and gastroenterology teams already screen T1D patients for celiac at diagnosis and periodically afterward. This new research doesn’t change that practice. It does, however, complicate what a “clear” result actually means.
The study followed 206 children with newly diagnosed T1D over 12 years, tracking their celiac antibody levels repeatedly. Among those who tested positive for the antibody at any point, half eventually tested negative — which might sound like good news. But two-thirds of those same children tested positive again later. The antibody was moving up and down, sometimes dipping below the detection threshold before climbing back. A child screened once during a natural dip could leave the clinic with a false reassurance.
What makes this pattern especially significant is that some children with confirmed intestinal damage — real, biopsy-proven celiac disease — never registered the high antibody levels that most current guidelines use as the signal to proceed to biopsy. Under standard protocols, those children might have been monitored rather than diagnosed. For families managing both T1D and celiac disease, or those worried about the combination, the takeaway is direct: ask your child’s care team how frequently they are screening, what the follow-up plan is when levels are borderline or mildly elevated, and whether a single normal result is sufficient to close the question.
For families like mine navigating celiac disease, this research is a useful reminder that screening protocols are not one-size-fits-all. The standard approach may need adjusting based on each child’s individual risk profile and how their numbers have moved over time.
Key Takeaways
- Children with type 1 diabetes need repeated celiac screenings over years — not a single test at diagnosis
- The primary celiac antibody (tTG-IgA) fluctuates in many T1D children, moving from positive to negative and back again
- About 5% of children with T1D in this study had biopsy-confirmed celiac disease, often without obvious symptoms
- Some confirmed celiac cases had antibody levels below the threshold that typically triggers a biopsy — meaning low positive results still matter
- Long-term, multi-dimensional monitoring is essential for catching celiac disease accurately in this high-risk group
The Science
Want to understand how this actually works? We’ll walk you through the technical details below and define every term. No medical degree required.
The Shared Biology Behind T1D and Celiac Disease
Type 1 diabetes and celiac disease are both autoimmune conditions — diseases where the immune system mistakenly attacks the body’s own tissue. In T1D, the target is the insulin-producing cells in the pancreas. In celiac disease, it is the lining of the small intestine. The two conditions share overlapping genetic risk factors, which is why children with one are far more likely to develop the other. This connection has been documented for decades, and routine celiac screening for T1D children is standard practice in most pediatric diabetes programs.
This study, conducted at Ankara University in Turkey and spanning 12 years, enrolled 282 newly diagnosed T1D children who had no prior celiac diagnosis. After excluding those with insufficient follow-up, 206 patients had enough longitudinal data to analyze.
What the Antibody Levels Actually Did
Researchers tracked each child’s tTG-IgA (tissue transglutaminase antibody immunoglobulin A) — the primary blood marker used to screen for celiac disease. When this antibody is elevated, it suggests the immune system is reacting to gluten in a way consistent with celiac disease. At high enough levels, current guidelines allow clinicians to diagnose celiac without a biopsy.
Of the 206 children, 24 (11.6%) tested positive for tTG-IgA at some point. Most — 70.8% — were flagged at the time of their T1D diagnosis. The remaining 29.2% were identified during subsequent routine screening, sometimes years later.
Here is where the picture becomes complicated. Of those 24 children who ever tested positive, only 10 were ultimately confirmed with celiac disease through intestinal biopsy — a rate of 4.8% across the full cohort. The remaining 14 showed serological fluctuation: antibody levels rose and fell without ever confirming to disease. Half became seronegative (their antibody level dropped back into the normal range), but two-thirds of those became positive again during the follow-up period.
This fluctuation matters because a snapshot test — one annual check — can catch a child during a temporary dip and return a reassuring negative. The disease biology has not changed; the measurement window has.
The Threshold Problem
Current European guidelines allow celiac diagnosis without a biopsy when tTG-IgA exceeds 10× the upper limit of normal (10×ULN), provided other criteria are met. The researchers in this study wanted to know whether that threshold made sense for children with T1D, given the antibody’s tendency to fluctuate in this population.
Using a statistical method called ROC (receiver operating characteristic) analysis — a technique for identifying the measurement cutoff that best distinguishes disease from non-disease — they found that a threshold of 7.3×ULN performed best in this cohort. At that level, the test achieved 100% specificity (no confirmed non-celiac children crossed this line) but only 70% sensitivity (30% of confirmed celiac cases still fell below it).
The sensitivity gap is the real concern. It means that even at an optimized threshold, roughly three in ten children with true celiac disease will not reach the level that triggers a biopsy recommendation. The study also found that 8.3% of biopsy-confirmed celiac cases had tTG-IgA levels below 3×ULN — a level some clinicians might treat as only mildly elevated and continue monitoring rather than investigating.
This echoes a pattern we have seen in other research: low antibody levels do not equal low disease burden. Earlier coverage here on ultra-short celiac disease in children with low tTG-IgA levels found the same disconnect — modest antibody signals can accompany real intestinal damage, particularly when the affected area is limited in scope.
Why Asymptomatic Presentation Raises the Stakes
One reason celiac disease can go undetected in children with T1D is that many present without classic gastrointestinal symptoms. Children already managing diabetes deal with significant dietary structure and routine health monitoring — a gut issue may be attributed to the diabetes, masked by other symptoms, or accepted as normal. The study found the majority of celiac cases in T1D children were asymptomatic or minimally symptomatic at diagnosis, making blood-based screening the primary detection tool. When that tool fluctuates, the margin for error shrinks.
The researchers conclude that a multi-dimensional approach is needed — repeated antibody testing at consistent intervals, clinical evaluation beyond the numbers, and willingness to investigate even modest or unstable elevations rather than defaulting to continued observation. They also recommend that in children with T1D, the decision to biopsy should not rest on a single elevated result, given how often those levels shift.
This is part of why non-invasive diagnostic alternatives are worth following. Research into biomarkers like urinary microRNAs as non-invasive celiac markers could eventually give clinicians additional tools to cross-check ambiguous antibody results — though those approaches remain in early development.
Related Coverage
- High prevalence of ultra-short celiac disease in children with low tTG-IgA levels: The risk of misdiagnosis without bulb biopsy
- Urinary miR-221-3p and miR-324-5p in combination with albuminuria as a promising model for non-invasive diagnosis of pediatric celiac disease
References
- Teke S, Tuna Kırsaclıoglu C, Turk NE, et al. Challenge of diagnosing celiac disease in pediatric type 1 diabetes mellitus: lessons from long-term serological surveillance. Postgraduate Medicine. 2026 Jun 12:1–8. doi: 10.1080/00325481.2026.2686458. PubMed