Effectiveness of the sorbitol H2 breath test in detecting histological damage among relatives of coeliacs.

BACKGROUND

Small intestinal lesions have a wide severity in coeliac disease (CD), and early diagnosis is important in preventing neoplastic and non-neoplastic disorders related to CD. The aim of this study was to compare the effectiveness of the sorbitol H2 breath test (H2-BT) and serological tests (antigliadin (AGA), antiendomysium (EMA) and anti-tissue transglutaminase (anti-tTG)) as screening tests in the detection and estimation of CD prevalence in 1st-degree relatives.

METHODS

Screening was performed in 111 1st-degree relatives of 37 coeliac families. Sorbitol H2-BT, AGA, EMA and anti-tTG antibodies were used to select the candidates for small-bowel biopsy. Relatives with abnormal serological tests and/or with sorbitol H2-BT positivity underwent a small-bowel biopsy. Small-bowel biopsy was also performed in relatives negative in all tests but with clinical complaints or suspected of having CD, and intestinal lesions were expressed according to the Marsh classification.

RESULTS

CD was diagnosed in 49/111 screened relatives (44.14%): 5 showed Marsh IIIc, 8 Marsh IIIb, 16 Marsh IIIa, 13 Marsh II and 7 Marsh I lesions. Nineteen relatives showed the classical form of the disease, while the subclinical and silent forms were recorded in 20 and 10, respectively. AGA, EMA and anti-tTG showed strong positivity only in severe intestinal damage (Marsh IIIb-c lesions) (but overall positivity was 36.73%, 38.78% and 44.89% for AGA, EMA and anti-tTG, respectively), while sorbitol H2-BT showed strong positivity also in patients with slight histological damage (Marsh I-IIIa) (overall positivity was 83.67%).

CONCLUSIONS

A significant proportion of coeliacs may be missed if relatives are screened by serology only, while the efficacy of sorbitol H2-BT in screening relatives is confirmed. This study confirms that neither a breath test nor serology can replace intestinal biopsy, which remains the gold standard for the diagnosis of CD.