Table 1.
The prevalence of celiac test positivity obtained with different ELISA assays with and without considering the DQ typing results
| No. | Tests considered to set a positive result | Cutoff | No of positive cases | Proportion of total study population in % (95% CI) | No of DQ2.5- or DQ8-positive cases | Proportion of DQ2.5- or DQ8-positive cases out of serology positives by this criteria in % | Proportion of serology positive by this criteria and DQ2.5- or DQ8-positive cases of total study population in % (95% CI) |
|---|---|---|---|---|---|---|---|
| 1 | Any diagnostic test positive (tTG IgA, DGP IgA, DGP IgG); EMA not considered | >20 U | 43 | 2.98 (2.10–3.86) | 18 | 41.86 | 1.25 (0.68–1.82) |
| 2 | Any diagnostic test positive (tTG IgA, DGP IgA, DGP IgG); EMA not considered | >30 U | 20 | 1.39 (0.79–1.99) | 10 | 50.00 | 0.69 (0.26–1.12) |
| 3 | Any diagnostic test positive (tTG IgA, DGP IgA, DGP IgG) and EMA positive | >20 U | 5 | 0.35 (0.05–0.65) | 5 | 100.00 | 0.35 (0.05–0.65) |
| 4 | Any diagnostic test positive (tTG IgA, DGP IgA, DGP IgG) and EMA positive | >30 U | 5 | 0.35 (0.05–0.65) | 5 | 100.00 | 0.35 (0.05–0.65) |
| 5 | Two diagnostic tests (tTG IgA, DGP IgA, DGP IgG) positive; EMA not considered | >20 U | 8 | 0.55 (0.17–0.93) | 7 | 87.50 | 0.49 (0.13–0.85) |
| 6 | Two diagnostic tests (tTG IgA, DGP IgA, DGP IgG) positive; EMA not considered | >30 U | 6 | 0.42 (0.09–0.75) | 6 | 100.00 | 0.42 (0.09–0.75) |
| 7 | All three diagnostic tests (tTG IgA, DGP IgA, DGP IgG) positive; EMA not considered | >20 U | 6 | 0.42 (0.09–0.75) | 6 | 100.00 | 0.42 (0.09–0.75) |
| 8 | All three diagnostic tests (tTG IgA, DGP IgA, DGP IgG) positive; EMA not considered | >30 U | 4 | 0.28 (0.01–0.55) | 4 | 100.00 | 0.28 (0.01–0.55) |
| 9 | DGP IgA and DGP IgG positive (irrespective of other tests) | >20 U | 7 | 0.49 (0.13–0.85) | 7 | 100.00 | 0.49 (0.13–0.85) |
| 10 | DGP IgA and DGP IgG positive (irrespective of other tests) | >30 U | 5 | 0.35 (0.05–0.65) | 5 | 100.00 | 0.35 (0.05–0.65) |
| 11 | DGP IgA and DGP IgG positive; tTG IgA negative (irrespective of other tests) | >20 U | 1 | 0.07 (0–0.21) | 1 | 100.00 | 0.07 (0–0.21) |
| 12 | DGP IgA and DGP IgG positive; tTG IgA negative (irrespective of other tests) | >30 U | 1 | 0.07 (0–0.21) | 1 | 100.00 | 0.07 (0–0.21) |
| 13 | tTG IgA positive (irrespective of other tests) | >20 U | 24 | 1.66 (1.00–2.32) | 10 | 41.67 | 0.69 (0.26–1.12) |
| 14 | tTG IgA positive (irrespective of other tests) | >30 U | 11 | 0.76 (0.31–1.21) | 7 | 63.64 | 0.49 (0.13–0.85) |
| 15 | EMA positive (irrespective of other tests) | ≥1:5 | 5 | 0.35 (0.05–0.65) | 5 | 100.00 | 0.35 (0.05–0.65) |
| 16 | tTG IgA and EMA positive (irrespective of other tests) | >20 U/≥1:5 | 5 | 0.35 (0.05–0.65) | 5 | 100.00 | 0.35 (0.05–0.65) |
ELISA: enzyme-linked immunosorbent assay; tTG IgA: human tissue transglutaminase immunoglobulin A; DGP IgA: deamidated gliadin peptide immunoglobulin A; DGP IgG: deamidated gliadin peptide immunoglobulin G; EMA: anti-endomysial immunoglobulin A antibodies; CI: confidence interval.