LAUSR

Abstract Background Hydrogen-methane breath testing is widely used in both gastroenterology and complementary therapies practice, yet current guidelines do not detail preparatory oral hygiene, nor provide standards for basal gas levels. Aims To review and compare a range of instructions for oral hygiene prior to hydrogen-methane breath testing provided by facilities offering hydrogen-methane breath testing services; and to investigate laboratory interpretation of basal gas values and describe similarities, differences and management. Results Twenty-five laboratories from six countries provided information regarding breath testing preparation. In practice, there is a lack of uniformity in instructions for oral hygiene prior to breath testing, and where instructions exist, little or no attention is given to adherence. A wide variance in accepted norms for basal gases exists between centres, which may impact on whether testing commences or not. It remains unknown whether elevation at baseline negates test results or should indicate deferring the test. Conclusion There is no consensus on management of elevated basal gas levels. To improve the reliability of diagnostic results obtained from breath testing there is a pressing need for clarification of the impact of the role of oral hygiene on results, which should guide standardisation of instructions to include preparation of the oral cavity.