Swart G R, van den Berg J W
Dept. of Gastroenterology and Hepatology, University Hospital Dijkzigt, Rotterdam, The Netherlands.
Scand J Gastroenterol Suppl. 1998;225:13-8.
Breath tests (BTs) are used in gastroenterological practice to study (patho)physiological and metabolic processes in an indirect way. In these tests the appearance in breath of a metabolite of a specific test substance is studied. The assumption underlying each BT is that one step-the process of interest-in the absorption and metabolism of the tracer is rate-limiting. Both hydrogen gas excretion and carbon dioxide appearance in breath can be studied. When a carbon-labelled test substance is used. the stable isotope 13C is preferred to the radioactive isotope 14C. Measurements of 13C in expired air are performed by mass spectrometry. Because of the indirect nature of BTs, involving a sequence of reactions and metabolic pools, they usually supply semiquantitative data. The tests are nevertheless useful because they often replace invasive techniques with a simple procedure that is safe because there is no radioactivity involved. BTs have been used to measure gastric emptying, the presence of Helicobacter pylori in the stomach, small-bowel bacterial overgrowth, exocrine pancreatic function as well as liver metabolic capacity; other potential applications of BTs are being studied.
呼气试验（BTs）在胃肠病学实践中用于以间接方式研究（病理）生理和代谢过程。在这些试验中，研究特定测试物质的代谢产物在呼气中的出现情况。每个呼气试验的基本假设是，示踪剂吸收和代谢过程中的一个步骤——感兴趣的过程——是限速步骤。呼气中的氢气排泄和二氧化碳出现情况均可进行研究。当使用碳标记的测试物质时，稳定同位素13C比放射性同位素14C更受青睐。呼出气体中13C的测量通过质谱法进行。由于呼气试验的间接性质，涉及一系列反应和代谢池，它们通常提供半定量数据。然而，这些试验是有用的，因为它们通常用一种简单的程序取代侵入性技术，这种程序是安全的，因为不涉及放射性。呼气试验已被用于测量胃排空、胃中幽门螺杆菌的存在、小肠细菌过度生长、外分泌胰腺功能以及肝脏代谢能力；呼气试验的其他潜在应用正在研究中。
