Storage conditions for stability of offline measurement of fractional exhaled nitric oxide after collection for epidemiologic research

BMC Pulmonary Medicine

Research Article

Hiroshi Kanegae¹  Masayuki Shima²  Yoshiko Yoda²  Naruhito Otani²  Hideki Hasunuma³ 

[1] Center for Environmental Information Science, 8-19 Yonban-cho, Chiyoda-ku, 102-0081, Tokyo, Japan;Department of Public Health, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, 663-8501, Hyogo, Japan;Department of Public Health, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, 663-8501, Hyogo, Japan;Center for Environmental Information Science, 8-19 Yonban-cho, Chiyoda-ku, 102-0081, Tokyo, Japan;

关键词: Cigarette smoking;    Epidemiologic research;    Exhaled nitric oxide;    Offline measurement;    Refrigeration;    Storage conditions;    Wheezing;   

DOI  :  10.1186/1471-2466-12-68

 received in 2012-06-08, accepted in 2012-10-29,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe measurement of fractional concentration of nitric oxide in exhaled air (FeNO) is valuable for the assessment of airway inflammation. Offline measurement of FeNO has been used in some epidemiologic studies. However, the time course of the changes in FeNO after collection has not been fully clarified. In this study, the effects of storage conditions on the stability of FeNO measurement in exhaled air after collection for epidemiologic research were examined.MethodsExhaled air samples were collected from 48 healthy adults (mean age 43.4 ± 12.1 years) in Mylar bags. FeNO levels in the bags were measured immediately after collection. The bags were then stored at 4°C or room temperature to measure FeNO levels repeatedly for up to 168 hours.ResultsIn the bags stored at room temperature after collection, FeNO levels were stable for 9 hours, but increased starting at 24 hours. FeNO levels remained stable for a long time at 4°C, and they were 99.7% ± 7.7% and 101.3% ± 15.0% relative to the baseline values at 24 and 96 hours, respectively. When the samples were stored at 4°C, FeNO levels gradually decreased with time among the subjects with FeNO ≥ 51 ppb immediately after collection, although there were almost no changes among the other subjects. FeNO levels among current smokers increased even at 4°C, although the values among ex-smokers decreased gradually, and those among nonsmokers remained stable. The rate of increase was significantly higher among current smokers than among nonsmokers and ex-smokers from 9 hours after collection onwards.ConclusionsStorage at 4°C could prolong the stability of FeNO levels after collection. This result suggests that valid measurements can be performed within several days if the samples are stored at 4°C. However, the time course of the changes in FeNO levels differed in relation to initial FeNO values and cigarette smoking.

【 授权许可】

Unknown   
© Yoda et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.