Takalo Reijo, Piirilä Päivi, Sovijärvi Anssi R A
Laboratory Department, Division of Clinical Physiology, Helsinki University Hospital, Helsinki, Finland.
Scand J Clin Lab Invest. 2008;68(8):830-2. doi: 10.1080/00365510802621158.
The objective of our study was to determine the repeatability of successive measurements of exhaled nitric oxide (NO) with a portable device (NIOX MINO). We assembled a sample of 332 pairs of repeated NO measurements acquired in the same session. The mean of the two successive measurements varied from 4.0 to 279.5 parts per billion (ppb). The mean coefficient of repeatability (CoR) of the entire study sample was 2.4 ppb. The difference between paired measurements increased slightly with increasing fractional exhaled nitric oxide (FENO); for the mean FENO of 24.0 ppb the calculated CoR was 2.2 and for the FENO of 54 ppb it was 3.2 ppb. The difference between paired observations for FENO values <50 ppb was significantly lower than that for values >50 ppb (p<0.001). The demonstrated repeatability of successive measurements with the device supports the view that, when the exhalation manoeuvre is technically valid and FENO is within normal limits, repeated determinations of FENO are generally not necessary for screening. In other cases, the mean value of two successive measurements would represent a more reliable measurement result.
我们研究的目的是确定使用便携式设备（NIOX MINO）连续测量呼出一氧化氮（NO）的可重复性。我们收集了在同一时间段内获得的332对重复的NO测量样本。两次连续测量的平均值在4.0至279.5十亿分之一（ppb）之间变化。整个研究样本的平均重复性系数（CoR）为2.4 ppb。配对测量之间的差异随着呼出一氧化氮分数（FENO）的增加而略有增加；对于平均FENO为24.0 ppb，计算出的CoR为2.2，对于FENO为54 ppb，CoR为3.2 ppb。FENO值<50 ppb时配对观察值之间的差异显著低于>50 ppb时的值（p<0.001）。该设备连续测量所显示的可重复性支持以下观点：当呼气操作在技术上有效且FENO在正常范围内时，一般无需重复测定FENO进行筛查。在其他情况下，两次连续测量的平均值将代表更可靠的测量结果。
