INTRAINDIVIDUAL VARIATION OF THE 13C-UREA BREATH TEST IN ASYMPTOMATIC HELICOBACTER PYLORI POSITIVE INDIVIDUALS

GM Matthews, RN Butler, P Cmielewski, RB Johnson & F Campbell.
Journal of Gastroenterology and Hepatology (2001), Volume 14; Supplement: A164

Australian Gastroenterology Week, 4-8 October 1999, Brisbane, Australia

ABSTRACT:

The 13C-urea breath test is a highly sensitive and specific method for the detection of Helicobacter pylori (H. pylon) and for determining the success of eradication therapy. However, variation in repeated 13C-urea breath tests taken at random has not been assessed. This is impor tant in the non-invasive assessment of novel therapeutic agents against H. pylori where suppression of the organism, as reflected by a diminished excretion of 13CO2, is to be determined. Intraindividual variation in delta over baseline (DOB) at 30 min as measured by the enrichment of 13C in expired CO2 following administration of 13C-urea, will determine how to interpret changes in DOB where total eradication has not been achieved. This study included 65 asymptomatic volunteers with mean age 59.2 ± 1.6 years (mean ± SEM) and with a range of 20 to 86 years who were recruited for an initial 13C-urea breath test. Twenty-one (32%) were H. pylori positive (DOB ³ 5) with a mean DOB of 23.6 ± 1.1 (mean ± SEM). All H. pylori positive volunteers were required thereafter to undertake 5 consecutive breath tests within the next 2 weeks. The intraindividual coefficient of variation (CV) was 26.76 ± 1.56% (mean ± SEM). DOB levels were distributed as such: DOB 5 to 10 (n =3), DOB 11 to 20 (n =7), DOB 21 to 30 (n =4), DOB >30 (n =7). The data (mean of 6 breath tests) indicate that groups of 12 or more patients with a DOB ³ 15, would be sufficient to detect a 33% change in DOB (mean of 2 breath tests), at a significance of 0.05 and a power of 0.9. We conclude that the 13C-urea breath test could be used to non-invasively assess the level of H. pylori infection following therapy.