Barth E, Tugtekin I, Weidenbach H, Wachter U, Vogt J, Radermacher P, Adler G, Georgieff M
Clinic of Anesthesiology, University of Ulm, Germany.
Isotopes Environ Health Stud. 1998;34(1-2):209-13.
Breath tests using 13C-labelled substrates require the measurement of 13CO2/12CO2 ratio in breath gas samples. Next to isotope ratio mass spectrometry (IRMS), which is very sensitive but also complex and expensive, alternatively isotope selective nondispersive infrared spectrometry (NDIRS) can be used to determine the 13CO2/12CO2 ratio in expired breath. In this study we compared NDIRS- with IRMS-results to investigate whether the less expensive and very simply to operate NDIRS works as reliable as IRMS. For this purpose we applicated 1- 13C-Phenylalanine to patients with advanced liver cirrhosis and healthy volunteers and took duplicated breath samples for IRMS and NDIRS at selected time points. Our data show a good correlation between these two methods for a small number of samples as required for simple breath tests. Longer series, where repeated measurements are required on the NDIRS instrument lead to a decreasing correlation. This indicates the superiority of IRMS concerning 13CO2-kinetics over longer time periods.
使用13C标记底物的呼气试验需要测量呼出气体样本中的13CO2/12CO2比值。除了非常灵敏但复杂且昂贵的同位素比值质谱法（IRMS）外，也可以使用同位素选择性非分散红外光谱法（NDIRS）来测定呼出气体中的13CO2/12CO2比值。在本研究中，我们比较了NDIRS和IRMS的结果，以调查成本较低且操作非常简单的NDIRS是否与IRMS一样可靠。为此，我们对晚期肝硬化患者和健康志愿者应用了1-13C-苯丙氨酸，并在选定的时间点采集了用于IRMS和NDIRS的重复呼气样本。我们的数据表明，对于简单呼气试验所需的少量样本，这两种方法之间具有良好的相关性。在需要对NDIRS仪器进行重复测量的较长序列中，相关性会降低。这表明在较长时间段内，IRMS在13CO2动力学方面具有优势。
