Qualitative and quantitative clinical evaluation of the laser-assisted ratio analyser for detection of Helicobacter pylori infection by C-13-urea breath tests

Objectives Currently, the C-13-urea breath test is the reference method for non-invasive diagnosis of Helicobacter pylori infection and therapy contro l. Therefore, new technologies have been developed to measure the ratio of (CO2)-C-13/(CO2)-C-12 in breath. The laser-assisted ratio analyser (LARA) d evice is based on optogalvanic effects of the stimulated CO2 molecules. Design In this study, the LARA system is prospectively compared to conventi onal isotope ratio mass spectrometry (IRMS) analysis of C-13-urea breath te sts. Methods The C-13-urea breath test was used to screen 103 patients for H. py lori infection. Breath samples were analysed by LARA and IRMS techniques. Results Seven breath tests could not be analysed by the LARA system, one by IRMS. Out of the remaining 95 breath tests, 13 were positive for H. pylori infection (13.7%). In reference to IRMS analysis (with a cut-off of >5 del ta parts per thousand at 30 min), LARA produced one false positive and one false negative breath test result giving a sensitivity of 92.3% and a speci ficity of 98.8%. The mean difference in delta over baseline values between IRMS and LARA measurements was 2.02 delta parts per thousand +/- 5.48 delta parts per thousand. Conclusion LARA allows the reliable qualitative evaluation of C-13-urea bre ath tests, but the quantitative results differ from IRMS findings. (C) 2001 Lippincott Williams & Wilkins.