Value of sweat conductivity testing in the diagnosis of cystic fibrosis in children
10.3760/cma.j.issn.0578-1310.2019.07.011
- VernacularTitle: 汗液电导率检测对儿童囊性纤维化的诊断价值分析
- Author:
Xinglan WANG
1
;
Zifu YIN
1
;
Yuelin SHEN
1
;
Hui LIU
1
;
Peter J. MOGAYZEL
2
;
Shunying ZHAO
1
Author Information
1. Department No. 2 of Respiratory Medicine, Beijing Children′s Hospital, Capital Medical University, Beijing 100045, China
2. Department of Pediatrics, Johns Hopkins Hospital, Cystic Fibrosis Center, Baltimore 21287, USA
- Publication Type:Clinical Trail
- Keywords:
Child;
Cystic fibrosis;
Sweat;
Conductivity
- From:
Chinese Journal of Pediatrics
2019;57(7):548-552
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To assess the diagnostic value of sweat conductivity testing in Chinese children with cystic fibrosis (CF).
Methods:This is a retrospective study. Sweat conductivity tests were conducted in 45 CF children (CF group) and 200 non-CF children (non-CF group) diagnosed with other chronic pulmonary diseases at the No. 2 Department of Respiratory Medicine, Beijing Children′s Hospital from May 2014 to June 2018. Pearson′s chi-square test was used to assess the differences between CF and non-CF groups. A receiver operating characteristic curve was constructed to calculate the best cut-off value to diagnose or rule out CF. The pulmonary function parameters (forced expiratory volume in the first second, forced vital capacity,forced expiratory flows at 75% of exhaled vital capacity) of CF children over 6 years old were analyzed. The relationship between sweat conductivity and pulmonary function was compared between the two groups (80-120mmol/L vs.>120mmol/L).
Results:The age of CF group was 9 (7,12) years old, 19 males (42%) and 26 females(58%); the age of non-CF group was 8 (5,11) years old, 106 males (53%) and 94 females(47%). The results of sweat conductivity test showed that sweat conductivity in CF group 108(99, 122) mmol/L was significantly higher than that in non-CF group 43(36, 52) mmol/L (χ2=207, P<0.01). A cut-off value of 80 mmol/L for CF diagnosis showed a sensitivity of 93.3% and a specificity of 98.5%. The receiver operating characteristic curve analysis suggested the best conductivity cut-off value for the diagnosis of CF was at 83.5 mmol/L,with a sensitivity of 93.3% and a specificity of 100%,and an area under the curve of 0.993 (95% confidence interval 0.985-1.000). The best conductivity cut-off value to rule out CF diagnosis was at 63.5 mmol/L,with a sensitivity of 97.8% and a specificity of 90.5%. There was no correlation between the level of sweat conductivity and the extent of pulmonary function decline.
Conclusions:Sweat conductivity testing can be used for the screening of CF in Chinese children. A diagnosis of CF should be considered if the value is greater than 80 mmol/L.
