Summary

2023 ACG update to the 2013 celiac disease guideline covering diagnosis, management, monitoring, and follow-up in adults and children. Confirms TTG IgA with total IgA as first-line serologic screen on a gluten-containing diet, with EGD and duodenal biopsy (1-2 bulb + ≥4 distal duodenum) to confirm diagnosis in most patients. Newly endorses a nonbiopsy diagnostic pathway in selected children (TTG IgA >10× ULN + confirmatory EMA) and discusses gluten-free diet adherence, mucosal healing, pneumococcal vaccination, oats, probiotics, and refractory disease.

Key Recommendations

Use TTG IgA plus total IgA as the initial serologic test in patients on a gluten-containing diet for suspected celiac disease.
If IgA-deficient, use IgG-based testing (DGP IgG and/or TTG IgG) for screening.
Confirm celiac disease with EGD and duodenal biopsies in adults; obtain 1-2 biopsies from the bulb (9 or 12 o’clock) and ≥4 from the distal duodenum, one specimen per forceps pass.
In symptomatic patients with high pretest probability (>5%), proceed to duodenal biopsy even if serology is negative.
A nonbiopsy diagnosis is a reasonable alternative in selected children with TTG IgA >10× ULN confirmed by EMA on a second blood sample, provided the family agrees.
Use HLA DQ2/DQ8 testing only in select scenarios (serology-histology discrepancy, evaluation of patients already on a GFD, or before gluten challenge); a negative result rules out celiac disease.
Treat with a strict lifelong gluten-free diet and refer all newly diagnosed patients to an expert dietitian.
Screen first-degree relatives of patients with celiac disease, and consider testing in patients with type 1 diabetes, unexplained transaminitis, iron-deficiency anemia, or malabsorptive symptoms.
Consider follow-up duodenal biopsy in adults after ~2 years on a GFD to assess mucosal healing; routine follow-up biopsy is not recommended in asymptomatic children.
Vaccinate adults with celiac disease against pneumococcus per CDC schedules given increased risk from functional hyposplenism.
Pure/uncontaminated oats can be included in a GFD, with monitoring for clinical or serologic relapse in the minority who are intolerant.
Do not recommend probiotics or gluten detection devices (food, urine, stool) as routine adjuncts; evidence is insufficient.
In nonresponsive celiac disease, systematically evaluate for gluten exposure, alternative diagnoses (IBS, SIBO, microscopic colitis, pancreatic insufficiency), and refractory celiac disease before escalating therapy.

Thresholds & Doses

Nonbiopsy diagnosis in children: TTG IgA >10× upper limit of normal plus positive EMA on a second blood sample.
Duodenal biopsy protocol: 1-2 specimens from duodenal bulb (9 or 12 o’clock) + ≥4 from distal duodenum; ≥4 total specimens nearly triples CD diagnostic yield (1.8% vs 0.7%).
Lymphocytic duodenosis defined as ≥25 intraepithelial lymphocytes per 100 epithelial cells.
High pretest probability threshold for biopsy despite negative serology: >5%.
Refractory celiac disease defined as persistent malabsorptive symptoms with villous atrophy despite strict GFD for >12 months.
Nonresponsive celiac disease defined as persistent symptoms/signs despite 6-12 months of gluten avoidance.
Adult positive predictive value of TTG IgA ≥10× ULN for CD: ~95% (basis for after-the-fact diagnosis when biopsy not feasible).
Suggested follow-up biopsy timing in adults: ~2 years after starting GFD (median time to mucosal healing in adults ~3 years; 95% of children heal by 2 years).
Clinical follow-up visits: 3, 6, and 12 months in year 1, then yearly or twice yearly thereafter.
Gluten-free food threshold (FDA): <20 ppm gluten; Nima sensor reliably detects at >40 ppm.
Pneumococcal vaccination in CD with functional asplenia: 1 dose PCV15 followed by PPSV23 ≥1 year later, OR 1 dose PCV20 alone.
Prevalence of celiac disease in first-degree relatives: 5-20% (highest in siblings, ~10% in other first-degree relatives).

Citations

Diagnosis section / Figure 1 — TTG IgA + total IgA initial testing algorithm and pediatric nonbiopsy criteria.
Diagnosis – Evidence and rationale — duodenal biopsy protocol (1-2 bulb + ≥4 distal duodenum).
Diet and long-term outcomes / Figure 2 — monitoring approach including follow-up biopsy at year 2.
Medical device use / Figure 3 — workup of nonresponsive and refractory celiac disease; RCD types 1 vs 2.
Pneumococcal vaccine section — CDC-based vaccination recommendations for adults with CD.
Screening / Table 4 — conditions warranting CD testing (T1DM, IDA, transaminitis, first-degree relatives).
Testing in Children section — TTG IgA preferred over combined TTG + DGP in children <2 years.
Nutrition section — safety of pure/uncontaminated oats with monitoring for relapse.