Objective To explore the predictive value of fat attenuation index(FAI)and fibrous plaque index(FPI)for the prognosis of patients with acute coronary syndrome(ACS).Methods A retrospective cohort study was conducted on 334 ACS patients undergoing percutaneous coronary intervention(PCI)in the First Affiliated Hospital of Army Military Medical University and Yongchuan Hospital of Chongqing Medical University from March 2021 to July 2023.All patients received coronary computed tomography angiography(CCTA)to measure FAI and FPI.According to the occurrence of major adverse cardiovascular events(MACE)with 1 year of follow-up,they were divided into MACE group(n=108)and non-MACE group(n=226).The baseline data,CCTA data and results of laboratory tests were collected and compared between the 2 groups.Multivariate logistic regression analysis was used to analyze the relationship of FAI and FPI with the prognosis of ACS patients,and ROC curve was drawn to evaluate its predictive efficiency.Results Among the 334 ACS patients,108(32.34%)experienced MACE.When compared with the non-MACE group,the MACE group exhibited significantly larger proportions of diabetes(72.22%vs 31.86%)and left main coronary artery disease(18.52%vs 7.08%),but lower success rate of operation(79.63%vs 93.81%,P<0.05).Radiologic results showed that the proportion of severe stenosis(20.37%vs 10.62%),FAI(-80.12±6.41 HU vs-72.34±7.09 HU)and FPI(0.58±0.41 vs 0.26±0.12)were obviously increased in the MACE group than the non-MACE group(P<0.05).Laboratory tests indicated that there were statistical differences between the 2 groups in high-density lipoprotein-cholesterol(HDL-C,1.20±0.15 vs 1.09±0.16 mmol/L),miR-126(0.91±0.12 vs 0.96±0.15)and SST2(38.45±5.67 vs 34.30±4.89 ng/mL,P<0.05).Multivariate Logistic regression analysis revealed that FAI(OR=1.200,95%CI:1.136～1.268),FPI(OR=63.157,95%CI:14.126～282.374),moderate stenosis(OR=1.332,95%CI:1.024～1.859),severe stenosis(OR=1.480,95%CI:1.074～2.039),miR-126(OR=0.007,95%CI:0.001～0.077),and sST2(OR=1.192,95%CI:1.113～1.277)were independent predictors of MACE(P<0.05).ROC curve analysis displayed that stenosis degree(AUC=0.622,95%CI:0.561～0.683,P=0.001),FAI(AUC=0.790,95%CI:0.741～0.839,P=0.001)and FPI(AUC=0.700,95%CI:0.638～0.761,P=0.001),miR-126(AUC=0.646,95%CI:0.584～0.707,P=0.001),sST2(AUC=0.700,95%CI:0.638～0.761,P=0.001)had certain predictive values for ACS prognosis.Conclusion Coronary FAI and FPI can be used as independent prognostic indicators of ACS patients,and their numerical changes are closely related to plaque stability and inflammatory state.

Objective:To explore the diagnostic value of fetal echocardiography (ECHO) for ventricular septal defect (VSD) and the causes of missed diagnosis and misdiagnosis by analyzing the standard of ECHO sections and image quality.Methods:A retrospective analysis was conducted on 94 VSD fetuses diagnosed by ECHO at Xiangtan Maternal and Child Health Care Hospital from January 2022 to June 2024. Clinical data including the anatomic subtypes, associated anomalies, chromosomal karyotype results, pregnancy outcomes, and neonatal ECHO results were collected and analyzed. Besides, by reviewing the ultrasound images from the institution's ultrasound workstation, a descriptive analysis was conducted on the ECHO section criteria and image quality in the missed and misdiagnosed cases.Results:Among 10 984 fetuses undergoing ECHO, a total of 94 cases of fetal VSD were detected (0.7%), including 45 (48%) isolated VSD and 49 (52%) non-isolated VSD cases. Anatomic distribution revealed perimembranous type predominance (67, 71%), followed by muscular (24, 26%), subarterial types (2, 2%), and perimembranous+muscular type (1, 1%). Among 29 missed diagnosis cases (fetal ECHO-negative but neonatal ECHO-confirmed VSDs), all were isolated VSD, muscular types accounted for 19 (66%), perimembranous types for 8 (27%), and subarterial types for 2 (7%). The causes of missed diagnosis include: technical limitation in 14 cases (48%), restricted cardiac acoustic window in 11 cases (38%), and operator-dependent factors in four cases (14%). All 18 misdiagnosed cases occurred in isolated VSD, with 15 cases of perimembranous and three cases of muscular types. The causes of misdiagnosis include: nine cases due to non-perpendicular beam alignment to perimembranous septum, six cases due to excessively high color flow gain,and three cases due to the misinterpretation of the right ventricular outflow tract flow above the aortic valve as VSD septal perforation blood flow. The sensitivity and specificity of fetal ECHO for diagnosing VSD were 76.42% and 99.83%. Among the 94 cases of fetal VSD, 38 cases (40%) underwent chromosomal karyotype analysis and chromosomal microarray analysis, which identified chromosomal karyotype abnormalities or pathogenic gene variants in 4/16 non-isolated VSDs (all perimembranous), while no anomalies were detected in 22 isolated VSDs. Pregnancy outcomes showed 31 terminations due to associated structural or chromosomal abnormalities versus 63 live births. In the live births, who underwent echocardiography in the neonatal period, 19 cases (30%) showed no VSD and were considered to have undergone spontaneous in utero closure, and persistent defects were found in 44 (70%).Conclusions:Fetal ECHO demonstrates high sensitivity and specificity in the diagnosis of fetal VSD. Critical quality control measures include individualized parameter adjustment and systematic multiplanar continuous scanning to minimize diagnostic errors. Isolated small and medium-sized muscular and perimembranous VSD usually have a good prognosis.

Objective:To evaluate the diagnostic efficacy of conventional ultrasound combined with contrast-enhanced ultrasound (CEUS) for detecting cervical lymph node metastasis in head and neck squamous cell carcinoma (HNSCC).Methods:This retrospective case control study included 259 patients (249 males and 10 females,aged 40-88 years with a median age of 63 years) who were pathologically diagnosed with HNSCC at the First Affiliated Hospital of Chongqing Medical University from April 2022 to August 2024. A total of 259 lymph nodes were assessed(78 pathologically positive nodes and 181 pathologically negative ones). Receiver operating characteristic (ROC) curves were plotted to compare the diagnostic efficacies of conventional ultrasound combined with CEUS and CT, MRI, or conventional ultrasound for cervical lymph node metastasis. Patients were randomly assigned to a training group ( n=208) and a validation group ( n=51) (8∶2). Univariate and multivariate Logistic regression were used to analyze the independent risk factors for lymph node metastasis prediction. A nomogram model was constructed based on independent risk factors. The model predictive efficacy was assessed by ROC curve, and model′s fit was evaluated by Hosmer-Lemeshow test. Results:The area under the curve (AUC) for conventional ultrasound combined with CEUS in predicting cervical lymph node metastasis in HNSCC was 0.923 (95% CI: 0.880-0.965), which was significantly higher than those for enhanced CT, cervical enhanced MRI, and conventional ultrasound [AUC were 0.820 (95% CI: 0.753-0.886), 0.802 (95% CI: 0.737-0.866), and0.836 (95% CI: 0.774-0.899), respectively].There were no statistically significant differences in clinical data between the two groups (all P>0.05). Univariate Logistic regression analysis showed that, among contrast-enhanced ultrasound features, the centripetal perfusion pattern, irregular perfusion defect type, and uneven distribution of contrast agent were significantly associated with cervical lymph node metastasis (all P<0.05). Among conventional ultrasound features, L/S ratio≤1.5, heterogeneous internal echoes, uneven cortex thickening, blurred corticomedullary boundary, loss of lymphatic gate structure, and peripheral or mixed type on color Doppler flow imaging were significantly associated with cervical lymph node metastasis (all P<0.05). Multivariate Logistic regression analysis indicated that the centripetal perfusion pattern, heterogeneous internal echoes, and uneven cortical thickening were independent risk factors for cervical lymph node metastasis (all P<0.05). A nomogram model was constructed based on the above independent risk factors, and offered an AUC of 0.933 (95% CI:0.890-0.976) in the training group, which was significantly higher than that for enhanced CT, enhanced MRI, conventional ultrasound, and conventional ultrasound combined with CEUS [AUC were 0.818 (95% CI:0.747-0.890), 0.807 (95% CI:0.739-0.875), 0.842 (95% CI: 0.777-0.908), and 0.921 (95% CI:0.876-0.967), respectively]. In the validation group, the AUC was 0.866 (95% CI:0.703-1.000), which was higher than that for cervical enhanced CT, enhanced MRI, and conventional ultrasound [AUC were 0.820 (95% CI:0.613-1.000), 0.711 (95% CI:0.478-0.943), and 0.748 (95% CI:0.515-0.982), respectively]. Conclusion:The combination of conventional ultrasound and CEUS has significant clinical application value in predicting cervical lymph node metastasis in HNSCC.

Objective:To evaluate the diagnostic efficacy of conventional ultrasound combined with contrast-enhanced ultrasound (CEUS) for detecting cervical lymph node metastasis in head and neck squamous cell carcinoma (HNSCC).Methods:This retrospective case control study included 259 patients (249 males and 10 females,aged 40-88 years with a median age of 63 years) who were pathologically diagnosed with HNSCC at the First Affiliated Hospital of Chongqing Medical University from April 2022 to August 2024. A total of 259 lymph nodes were assessed(78 pathologically positive nodes and 181 pathologically negative ones). Receiver operating characteristic (ROC) curves were plotted to compare the diagnostic efficacies of conventional ultrasound combined with CEUS and CT, MRI, or conventional ultrasound for cervical lymph node metastasis. Patients were randomly assigned to a training group ( n=208) and a validation group ( n=51) (8∶2). Univariate and multivariate Logistic regression were used to analyze the independent risk factors for lymph node metastasis prediction. A nomogram model was constructed based on independent risk factors. The model predictive efficacy was assessed by ROC curve, and model′s fit was evaluated by Hosmer-Lemeshow test. Results:The area under the curve (AUC) for conventional ultrasound combined with CEUS in predicting cervical lymph node metastasis in HNSCC was 0.923 (95% CI: 0.880-0.965), which was significantly higher than those for enhanced CT, cervical enhanced MRI, and conventional ultrasound [AUC were 0.820 (95% CI: 0.753-0.886), 0.802 (95% CI: 0.737-0.866), and0.836 (95% CI: 0.774-0.899), respectively].There were no statistically significant differences in clinical data between the two groups (all P>0.05). Univariate Logistic regression analysis showed that, among contrast-enhanced ultrasound features, the centripetal perfusion pattern, irregular perfusion defect type, and uneven distribution of contrast agent were significantly associated with cervical lymph node metastasis (all P<0.05). Among conventional ultrasound features, L/S ratio≤1.5, heterogeneous internal echoes, uneven cortex thickening, blurred corticomedullary boundary, loss of lymphatic gate structure, and peripheral or mixed type on color Doppler flow imaging were significantly associated with cervical lymph node metastasis (all P<0.05). Multivariate Logistic regression analysis indicated that the centripetal perfusion pattern, heterogeneous internal echoes, and uneven cortical thickening were independent risk factors for cervical lymph node metastasis (all P<0.05). A nomogram model was constructed based on the above independent risk factors, and offered an AUC of 0.933 (95% CI:0.890-0.976) in the training group, which was significantly higher than that for enhanced CT, enhanced MRI, conventional ultrasound, and conventional ultrasound combined with CEUS [AUC were 0.818 (95% CI:0.747-0.890), 0.807 (95% CI:0.739-0.875), 0.842 (95% CI: 0.777-0.908), and 0.921 (95% CI:0.876-0.967), respectively]. In the validation group, the AUC was 0.866 (95% CI:0.703-1.000), which was higher than that for cervical enhanced CT, enhanced MRI, and conventional ultrasound [AUC were 0.820 (95% CI:0.613-1.000), 0.711 (95% CI:0.478-0.943), and 0.748 (95% CI:0.515-0.982), respectively]. Conclusion:The combination of conventional ultrasound and CEUS has significant clinical application value in predicting cervical lymph node metastasis in HNSCC.

Objective:To explore the diagnostic value of fetal echocardiography (ECHO) for ventricular septal defect (VSD) and the causes of missed diagnosis and misdiagnosis by analyzing the standard of ECHO sections and image quality.Methods:A retrospective analysis was conducted on 94 VSD fetuses diagnosed by ECHO at Xiangtan Maternal and Child Health Care Hospital from January 2022 to June 2024. Clinical data including the anatomic subtypes, associated anomalies, chromosomal karyotype results, pregnancy outcomes, and neonatal ECHO results were collected and analyzed. Besides, by reviewing the ultrasound images from the institution's ultrasound workstation, a descriptive analysis was conducted on the ECHO section criteria and image quality in the missed and misdiagnosed cases.Results:Among 10 984 fetuses undergoing ECHO, a total of 94 cases of fetal VSD were detected (0.7%), including 45 (48%) isolated VSD and 49 (52%) non-isolated VSD cases. Anatomic distribution revealed perimembranous type predominance (67, 71%), followed by muscular (24, 26%), subarterial types (2, 2%), and perimembranous+muscular type (1, 1%). Among 29 missed diagnosis cases (fetal ECHO-negative but neonatal ECHO-confirmed VSDs), all were isolated VSD, muscular types accounted for 19 (66%), perimembranous types for 8 (27%), and subarterial types for 2 (7%). The causes of missed diagnosis include: technical limitation in 14 cases (48%), restricted cardiac acoustic window in 11 cases (38%), and operator-dependent factors in four cases (14%). All 18 misdiagnosed cases occurred in isolated VSD, with 15 cases of perimembranous and three cases of muscular types. The causes of misdiagnosis include: nine cases due to non-perpendicular beam alignment to perimembranous septum, six cases due to excessively high color flow gain,and three cases due to the misinterpretation of the right ventricular outflow tract flow above the aortic valve as VSD septal perforation blood flow. The sensitivity and specificity of fetal ECHO for diagnosing VSD were 76.42% and 99.83%. Among the 94 cases of fetal VSD, 38 cases (40%) underwent chromosomal karyotype analysis and chromosomal microarray analysis, which identified chromosomal karyotype abnormalities or pathogenic gene variants in 4/16 non-isolated VSDs (all perimembranous), while no anomalies were detected in 22 isolated VSDs. Pregnancy outcomes showed 31 terminations due to associated structural or chromosomal abnormalities versus 63 live births. In the live births, who underwent echocardiography in the neonatal period, 19 cases (30%) showed no VSD and were considered to have undergone spontaneous in utero closure, and persistent defects were found in 44 (70%).Conclusions:Fetal ECHO demonstrates high sensitivity and specificity in the diagnosis of fetal VSD. Critical quality control measures include individualized parameter adjustment and systematic multiplanar continuous scanning to minimize diagnostic errors. Isolated small and medium-sized muscular and perimembranous VSD usually have a good prognosis.

ObjectiveTo observe the intervention effect of Huaiqihuang granules （HQH） on immunoglobulin A vasculitis nephritis （IgAVN） mice and explore the underlying therapeutic mechanism. MethodFifty SPF-grade male Kunming mice were randomly divided into a normal group， an IgAVN model group， a dexamethasone group （2.5 mg·kg^-1·d^-1）， a low-dose HQH group （4 g·kg^-1·d^-1）， and a high-dose HQH group （8 g·kg^-1·d^-1）. The mouse model was established using oral administration of gliadin combined with intravenous injection of India ink. After successful modeling， the mice were euthanized after 4 weeks of gastric gavage according to groups. The 24 h urinary total protein （24 h UTP）， urine β₂-microglobulin （β₂-MG）， serum total protein， albumin， IgA， etc. were detected in each group. Flow cytometry was used to determine the proportion of T helper 17 （Th17） cells in spleen cell suspension. Western blot was employed to detect the expression of adenosine 5'-monophosphate-activated protein kinase α （AMPKα）， phosphorylated AMPKα （p-AMPKα）， acetyl-CoA carboxylase 1 （ACC1）， and phosphorylated ACC1 （p-ACC1） in Th17 cells. Pathological changes in the spleen and kidneys were observed. ResultCompared with the normal group， the IgAVN model group showed significant increases in 24 h UTP， urine β₂-MG， total cholesterol （P<0.05）， serum interleukin-17 （IL-17）， IgA， Th17 proportion in the spleen cell suspension， and IL-17 expression in the spleen tissue （P<0.01）， and significantly decreased serum total protein， albumin， p-AMPKα/AMPKα， and p-ACC1/ACC1 expression of Th17 cells （P<0.01）. Compared with the IgAVN model group， in the 4th week， the 24 h UTP， urine β₂-MG， serum IL-17， IgA levels， and renal IgA deposition were significantly reduced in each treatment group （P<0.01）， and the Th17 proportion and IL-17 expression in spleen tissue were significantly decreased （P<0.05， P<0.01）. Serum albumin levels significantly increased （P<0.05）. Compared with the IgAVN model group， the dexamethasone group and the high-dose HQH group showed increases in serum total protein （P<0.01）， p-AMPKα/AMPKα， and p-ACC1/ACC1 expression of Th17 cells （P<0.05， P<0.01）. The high-dose HQH group showed a significant decrease in total cholesterol level （P<0.05）. Various treatment groups showed different degrees of improvement in spleen and kidney pathological changes. ConclusionHQH may affect Th17 cell differentiation by regulating the AMPK/ACC pathway， correcting immune inflammatory disorders， and exerting therapeutic effects on IgAVN.

Objective:To explore the expression features of cytochrome C oxidase subunit Ⅰ (MT-CO1), BCL2 interacting protein 3 (BNIP3) and interleukin (IL)-1β in the liver of MRL/lpr lupus mice.Methods:The mRNA and protein levels of MT-CO1, BNIP3, IL-1β, p16 and p21 in lupus mice and control mice were detected by polymerase chain reaction (PCR) and Western blot, the IL-1β expression site were detected by hematoxylin and eosin (HE) staining and immunohistochemical method, and themalondialdehyde (MDA) was detected by colorimetry. Hepatocytes and macrophages were stimulated with lipopolysaccharide (LPS), while hepatocytes were also cultured with supernatants obtained after macrophages stimulated with LPS, and the mRNA and protein levels of MT-CO1, BNIP3 and LC3B, as well as p16 and p21 expression, were determined by qPCR and Western blot. The expression of mitochondrial reactive oxygen species (mtROS) was detected by immunofluorescence. One way Analysis of Variance (ANOVA) was used to compare the mean of each group, and LSD method was used to compare the means of multiple samples, and Tamhane's T2 method was used to compare the means of multiple samples when the variance was uniform. Results:The results of PCR showed that the mRNA levels of MT-CO1 and BNIP3 in the liver tissue of the lupus group (0.14±0.04; 0.16±0.05) were significantly lower than those of the control group (0.11±0.04; 0.16±0.06), and the differences were statistically significant ( t=7.16, P<0.001; t=4.54, P<0.001). The expression levels of IL-1β, p16 and p21 in the lupus group (2.06±0.69; 0.37±0.14; 0.16±0.06) were significantly higher than those of the control group (0.23±0.06; 0.25±0.08; 0.11±0.04) ( t=9.58, P<0.001; t=24.35, P<0.001; t=22.36, P<0.001). The results of Western blot were consistent with those of PCR. HE staining showed lymphocyte infiltration in the liver tissue of lupus mice, and immunohistochemistry showed IL-1β in the liver tissue of lupus mice. The positive cells were mainly concentrated in the sinusoids, and the expression of hepatic parenchymal cells was not rearkable. The content of MDA in liver tissue of the lupus group (0.19±0.10) was higher than that of the control group (0.17±0.09), and the difference was statistically significant ( t=4.33, P=0.005). LPS directly stimulated AML12 hepatocytes (0.069±0.028; 0.17±0.07). The PCR results showed that compared with the control group (0.176±0.072; 0.08±0.03), the expression of MT-CO1, and BNIP3 were not significantly different ( t=1.01, P=0.337; t=0.88, P=0.399). The expression of IL-1β was significantly higher when incubated with the supernatants of LPS stimulated macrophages (0.28±0.09) compared than that of the control group (0.15±0.05) ( t=28.26, P<0.001). The results of PCR showed that the mRNA levels of MT-CO1 and BNIP3 in the LPS stimulated group (0.046±0.026; 0.17±0.05) were significantly lower than those in the control group (0.143±0.083; 0.18±0.06), and the differences were statistically significant ( t=7.52, P<0.001; t=4.24, P<0.001), The expression of p16 and p21 in LPS stimulated group (0.29±0.09; 0.27±0.09) were significantly higher than those in the control group (0.18±0.06; 0.22±0.07) ( t=13.54, P<0.001; t=8.69, P<0.001). The results of Western blot were consistent with those of PCR. Immunofluorescence showed that the fluorescence intensity of mtROS in LPS stimulated group (0.25±0.10) was higher than that in the control group (0.08±0.03), and the difference was statistically significant ( t= 4.86, P<0.001). Conclusion:Immune-mediated inflammation in the liver tissue of lupus mice can stimulate liver parenchymal cells to cause intracellular mitochondrial dysfunction. However, the mechanism of liver organ damage in lupus mice is not limited to the immune-mediated inflammation of immune active cells, but also include parenchymal cell mitochondrial dysfunction.

OBJECTIVE: In order to find whether there is the correlation between the non-oil particle filtration efficiency(PFE) and the bacterial filtration efficiency(BFE) of medical surgical masks. METHODS: Non-oil particle filtration efficiency and bacterial filtration efficiency were compared and analyzed through the test data of medical surgical masks from 2012 to 2018. RESULTS: When the non-oil particle filtration efficiency of medical surgical mask is over 80%, the bacterial filtration efficiency can reach 95%. CONCLUSIONS In order to reach the requirement of 95% bacterial filtration efficiency, surgical medical mask must improve the limit of non-oil particle filtration efficiency. The results of data analysis can provide reference for emergency inspection and filter material rapid inspection, and also provide reference for the revision of YY 0469 standard.
Filtration ; Masks ; Particle Size

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.

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.