Reference ranges for induced sputum eosinophil counts in Korean adult population

Abstract

BackgroundInduced sputum analyses are widely utilized to evaluate airway inflammation in asthmatics. However, the values have not been examined in Korean adults.ObjectiveThe purpose of this study is to determine reference ranges for induced sputum eosinophils and their influencing factors in Korean adults.MethodsA total of 208 healthy nonasthmatic adults were recruited. Sputum induction and processing followed the international standard protocols.ResultsAdequate sputum samples were successfully collected from 81 subjects (38.9%). The upper 90 percentile for sputum eosinophil was calculated as 3.5%. The median value of eosinophil count percentage was significantly higher in subjects with atopy than those without atopy (median, 1.6%; range, 0-11.0% vs. median, 0%; range 0-3.6%, p=0.030). However, no significant correlations were found with age, gender, body mass index, smoking status, blood eosinophil, or fractional exhaled nitric oxide levels.ConclusionCurrent study was the first attempt to determine the reference ranges of induced sputum eosinophils in Korean adults. The cutoff value for sputum eosinophilia was 3.5%, and was significantly associated with atopy.

Fractional Exhaled Nitric Oxide: Comparison Between Portable Devices and Correlation With Sputum Eosinophils

“…The correlation between FeNO and ISE has been reported variably. The correlation coefficients ranged from 0.094 (n=81, P =0.406) in healthy nonasthmatic adults, 23 to 0.35 (n=25, P =0.09) in asthmatic children, 24 to 0.48 (n=35, P =0.003) in atopic asthmatic adults, 25 to 0.493 (n=21, P <0.05) in adults with NAEB, to 0.576 (n=14, P <0.05) in adults with asthma, 26 to 0.59 (n=566, P <0.001) in adults with stable asthma, 2 to 0.62 (n=78, P <0.0001) in adults with mild to moderate asthma using ICS. 27 The correlation seems to be present only in patients with asthma or NAEB, and 70% of our study population had these diseases.…”

“…In this study, only 19 (47%) patients provided induced sputum containing less than 30% squamous cell. Recent study by Kim et al 23 reported 19.8% of the induced sputum were inadequate using the 30% cutoff value. We believe the more generous criterion allows more samples to be analyzed without sacrificing the accuracy of the test.…”

Reference value of induced sputum cell counts and its relationship with age in healthy adults in Guangzhou, Southern China

“…The sputum neutrophil counts reported in our study are similar to Caucasians, 2 but higher than Korean population who are Mongolians as we are. 8 Therefore, we believe different ethnic groups are not the main reason causing differences in the sputum cell counts. According to us, air pollutants might affect sputum cell counts.…”

“…Belda et al 2 report that sputum eosinophil of healthy females are higher than males, while another two studies 5,8 do not find the impact of gender on sputum eosinophil count. In the current study, neither sputum total cell counts nor differential cell counts are different between males and females in each age group or in subjects at all ages.…”

KAAACI Standardization Committee report on the procedure and application of induced sputum examination

“…김민혜, 1 김미영, 2 임경환, 3 양민석, 4 송우정, 5 이정민, 6 서동인, 7 신유섭, 8 권재우, 9 김세훈, 10 김상헌, 11 이병재, 12 조상헌, 5 정재우, 13 대한천식알레르기학회 표준화위원회 1 이화여자대학교 의과대학 내과학교실, 2 인제대학교 부산백병원 내과, 3 국군수도병원 내과, 4 서울대학교 보라매병원 내과, 5 서울대학교 의과대학 내과학교실, 6 연세대학교 원주 의과대학 소아청소년과학교실, 7 서울대학교 의과대학 소아청소년과학교실, 8 아주대학교 의과대학 알레르기내과학교실, 9 강원대학교 의과대학 내과학교실, 10 서울대학교 분당병원 내과, 11 한양대학교 의과대학 내과학교실, 12 성균관대학교 의과대학 내과학교실, 13 중앙대학교 의과대학 내과학교실 KAAACI Standardization Committee report on the procedure and application of induced sputum examination 검사 시행 Table 2).…”