An inter- and intra-laboratory comparison of breath ¹³CO₂analysis

Background: (13) C breath test analysis requires accurate (13) CO2 measurements. Aim: To perform a multicentre study to evaluate the repeatability and reproducibility of breath (13) CO2 analysis. Methods: Two series of 25 paired randomly coded tubes (each consisting of 23 (13) CO2 -enriched breath samples and two samples of standard reference pure CO2 with certified delta (13) C-PDB ) were sent to participating centres for (13) CO2 measurement. Each series of tubes was analysed 10 days apart. The repeatability and reproducibility of (13) C measurements was assessed by Mandel's k and h statistics. Results: Twenty-two centres participated in the study: 18 showed good inter- and intra-laboratory variability, whilst four showed abnormally high inter- or intra-laboratory variability. Breath test results were also significantly affected by the accuracy of the (13) C analytical procedures. Conclusions: A low accuracy of (13) C measurements may significantly affect the results of breath tests, leading to inappropriate clinical decisions. Standardization of (13) C analysis is required to guarantee optimal (13) C measurements and accurate (13) C breath test results.