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A multicentre evaluation of the laser assisted ratio analyser (LARA): a novel device for measurement of 13 CO 2 in the 13 C‐urea breath test for the detection of Helicobacter pylori infection
Author(s) -
Cave D. R.,
Veldhuyzen van Zanten S.,
Carter E.,
Halpern E. F.,
Klein S.,
Prather C.,
Stolte M.,
Laine L.
Publication year - 1999
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1046/j.1365-2036.1999.00534.x
Subject(s) - medicine , analyser , gastroenterology , nuclear medicine , breath test , endoscopy , prospective cohort study , chromatography , helicobacter pylori , chemistry
Background : The laser assisted ratio analyser (LARA) was developed as a novel device to measure 13 CO 2 in the urea breath test for the detection of H. pylori infection. The analyser was tested in a prospective multicentre study in 444 patients in North America (Phase 1) followed by second study involving 160 patients (Phase 2). Methods : Patients undergoing endoscopy for clinical indications had antral and gastric biopsies taken for histological examination, culture and CLO test. One hour after endoscopy, a baseline breath sample was obtained, 100 mg of 13 C‐urea were ingested and breath samples were obtained at 30 and 60 min post ingestion. Data obtained with the LARA were compared with the results of culture, rapid urease testing and central pathology in two different combinations {reference standards}. The study was conducted in two phases: in Phase 2, a modification was made to the LARA that improved the removal of water vapour from the breath sample. Results : In Phase I, data from 331 patients were analysed using a cut off of (delta) 7.8 ± 0.8, the sensitivity of the method was 91.7% and the specificity was 86.5%, using the reference standard of 2 of 3 tests (CLO, culture or histology) being positive. Positive and negative predictive values were, respectively, 85.2% and 92.5%. In Phase 2 of the study, 160 patients were enrolled and 141 patients were analysed using the same standards. We used the same reference standards but with a cut off of (delta) 6.1 ± 0.6. The sensitivity and specificity increased to 96.8% and 98.6%, respectively. Positive and negative predictive values were, respectively, 98.4% and 97.3%. The detection rates for H. pylori were similar in patients with peptic ulcer or H. pylori associated gastritis. Conclusions : The LARA provides an accurate non‐invasive means of detecting 13 CO 2 in the 13 C‐urea breath test for H. pylori in a multicentre clinical environment that compares well with invasive ‘gold standard’ methods.