Serological tests highly accurate for coeliac disease diagnosis

Serological tests can reliably detect coeliac disease in children and adults, with the sensitivity of anti-tissue transglutaminase (tTG) being sufficient to rule out the disease while the high specificity of endomysial antibody (EMA) being useful for ruling in a diagnosis of the disease, according to the results of a systematic review and meta-analysis.

Researchers searched multiple online databases for studies that assessed the diagnostic accuracy of serological tests against duodenal biopsy for coeliac disease. They used QUADAS-2 to evaluate the risk of bias, then applied bivariate random-effects meta-analyses to estimate serology sensitivity and specificity at the commonly reported thresholds.

A total of 113 studies involving 28,338 participants were included in the meta-analysis, of which 23 were conducted in adults, 48 in children, and 33 in a mixed (adults and children) or an age-unspecified population. The mean age of adults was 43.6 years, while that of children was 6.3 years. On average, 66 percent of adults and 52 percent of children were female. The serological tests evaluated were immunoglobulin A (IgA) tTG, immunoglobulin G (IgG) tTG, IgA EMA, IgG EMA, IgA deamidated gliadin peptide (DGP), IgG DGP, and IgA antiactin antibodies (AAA).

Pooled data revealed that serological tests yielded high accuracy for detecting coeliac disease. IgA tTG had a sensitivity of 90.7 percent (threshold, 15 U/mL) in adults and 97.7 percent (threshold, 20 U/mL) in children. Specificity was slightly lower at 87.4 percent and 70.2 percent, respectively.

Meanwhile, IgA EMA had a slightly lower sensitivity at 88.0 percent (threshold, 1:5) in adults and 94.5 percent (threshold, 1:10). But specificity was high at 99.6 percent and 93.8 percent, respectively.

The findings suggest that tTG is better at ruling out than at ruling in a diagnosis of coeliac disease, especially in children, and that EMA may be used to rule in coeliac disease, possibly as a secondary test following an initial positive IgA tTG test.