THE (13)CARBON UREA BREATH TEST FOR THE NONINVASIVE DETECTION OF HELICOBACTER-PYLORI IN CHILDREN - COMPARISON WITH CULTURE AND DETERMINATION OF MINIMUM ANALYSIS REQUIREMENTS

Background: The purpose of the study was to determine the accuracy of the labelled (13)carbon urea breath test for the diagnosis of Helicoba cter pylori in children and to simplify the (13)carbon urea breath tes t in identifying the most discriminating sampling time. Methods: H. py lori was searched for in 100 children aged 10.5 +/- 4.5 years by histo logy, bacteriological counts, and culture on antral biopsies together with serology and (13)carbon urea breath test. Breath samples were obt ained before ingestion (TO) of 75 mg urea-C-13 and every 10 minutes af ter until T60. (CO2)-C-13 excess ratio was measured by isotope ratio m ass spectrometry, and values expressed as delta per mil over baseline enrichment (delta (CO2)-C-13). The arithmetic mean (M delta (CO2)-C-13 ) of T20 to T60 values was calculated and the test-considered positive with M delta (CO2)-C-13 higher than M delta (CO2)-C-13 + 3 SD as dete rmined in noninfected children. Results: M delta (CO2)-C-13 of noninfe cted children as assessed by culture was 1.4 +/- 0.6 per mil, determin ing a positive cut-off value of 3.44 per mil. M delta (CO2)-C-13 was c orrelated in 11 children with biopsy bacteriological counts. Both cult ure and (13)carbon urea breath test were positive in 38 of 100 childre n, without any discordance. Plotting (13)carbon urea breath test resul ts at each sampling time versus M delta (CO2)-C-13 showed weaker corre lations at T20, T30, T50, and T60, than at T40. The two-sample method at TO and T30, T40, T50, had high sensitivity and specificity. Single- sample analysis obtained at T40 gave a comparable sensitivity and a sl ightly reduced specificity. Conclusion: (13)carbon urea breath test is sensitive and specific in children. Two samples collected at TO and T 40 provide the most discriminating procedure.