14C in diagnostics of Helicobacter pylori infection of gastrointestinal tract

Investigations aiming to develop diagnostication of Hp by use non-invasive methods have been concentrated on 14C labelled urea, however 13C stable isotope was also successfully applied in this purpose. In the described breath test each one of a group of patients subjected to diagnostication was administered 92.5 kBq as the 14CO(NH2)2 in form of the water solution. Specific 14CO2 activity in breath out air reached its maximum (ca. 50 Bq/mmol) after 10 minutes for Hp(+) patients. Direct sorption of CO2 in Hydroxide of Hyamine (1-mol solution in methanol) with phenolophtaleine as pH indicator, and following measurement in LS spectrometer TRI-CARB 2550-TR/AB, Canberra-Packard with admixed 10 ml liquid scintillator (Perma-Fluor or Insta-Fluor) enabled diagnostication of Hp with sensitivity: 100% and specificity: 92.6%. Application of 13C labelled urea is less complicated with respect to sample preparation, and can be entirely automated, but requires expensive mass-spectrometer and highly enriched in 13C urea (at least 99.0%) for results comparable to the 14C. (author)