Objective To evaluate the commutability of certified reference material IRMM ERM-DA 471/IFCC for cystatin C measurement among 8 methods.Methods 46 individual samples used for the commutability study were residual serum samples collected from clinical laboratories.The individual samples interspersedwith pooled sera and the certified reference material IRMM ERM-DA 471/IFCC and the whole set of samples was divided into 2 subsets for measurements in 2 days.The measurements were performed by8 different methods o.The samples were measured in duplicate order.Calibration was performed every day. Passing-Bablok regression was performed to compare the slopes and intercepts of mean values of the serum samples derived from different methods. Pearson correlation cofficient was also calculated. Deming regeression and 95%confidence intervals were calculated to evaluate the statistics commutability of ERM-DA 471/IFCC.The minimal specification of bias derived from biological variations was calculated to evaluate the clinical commutability.Results The within-laboratory CVs of pool sera ranged from 0.5% to 4.0%.The Passing-Bablok slope ranged from 0.765 to 1.311 and intercepts ranged from -0.04 to 0.241.The determination coefficient of Pearson regression ranged from 0.988 to 0.999.Deming regeression and 95%confidence intervals demonstrated commutability of ERM-DA 471/IFCC in 4/28 (14.3%) methods pairs. The minimal specfication bias ( 5.12%) demonstrated commutability of ERM-DA 471/IFCC in15/28 (53.6%) methods pairs.Conclusions The ERM-DA 471/IFCC domonstrated poor commutability between some methods pairs. The commutability of ERM-DA 471/IFCC should be evaluated before used as calibrators.

Objective: To investigate the value of fibrinogen to albumin ratio (FAR) at admission on predicting spontaneous recanalization of infarct-related artery (IRA) in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: Clinical data from 255 acute STEMI patients ((61.1±11.2) years old, 189 males) who underwent emergency coronary angiography within 12 hours in our hospital from December 2015 to April 2018 were retrospectively analyzed. The acute STEMI patients were divided into non-spontaneous recanalization group (thrombolysis in myocardial infarction (TIMI) flow grade 0-1, 203 cases) and spontaneous recanalization group (TIMI flow grade 2-3, 52 cases). Multivariate logistic regression analysis was used to evaluate related factors of IRA spontaneous recanalization. The receiver operating characteristic (ROC) curve was used to evaluate the value of FAR in predicting spontaneous coronary recanalization. Results: There was no significant difference in age,gender, hypertension, diabetes, smoking,systolic blood pressure,diastolic blood pressure,heart rate, duration of chest pain, type of infarction, infarct-related artery, door-to-balloon time, and drug used before admission between non-spontaneous recanalization group and spontaneous recanalization group (all P>0.05). The FAR and high-sensitivity C-reactive protein levels were significantly lower in the spontaneous recanalization group than in the non-spontaneous recanalization group (8.20±1.85 vs. 11.02±2.75, P<0.001; (6.87±3.36) g/L vs. (8.51±3.72) g/L, P=0.004). Multivariate logistic regression analysis showed that FAR (OR=0.492, 95%CI 0.354-0.686, P<0.001), serum uric acid (OR=0.994, 95%CI 0.989-0.999, P=0.018) and high-sensitivity C-reactive protein (OR=0.774, 95%CI 0.614-0.975, P=0.030) were independent negative correlation with spontaneous recanalization of infarct-related artery in patients with acute STEMI. The ROC curve showed that the area under the curve of FAR predicting spontaneous recanalization of infarct-related artery in patients with acute STEMI was 0.807 (95%CI 0.630-0.758, P<0.001), and the diagnostic threshold was 9.26, the sensitivity was 76.9%, the specificity was 75.9%. Conclusion The level of admission FAR has certain predictive value for spontaneous recanalization of infarct-related arteries in patients with acute STEMI.

Objective: To understand the present situation of physical activity and its influencing factors, and to provide a reference for improving the level of physical activity and making the intervention measures. Methods: The method of random stratification was used to select 4 740 pre school children aged 3-6 from 17 kindergartens in 12 counties and districts of Nanchang City, The questionnaire of physical activities of young children and the questionnaire of parents of physical activities of young children were applied to conduct a survey. Results: Compared with weekday PA and MVPA, preschool children’s weekends decreased, SB increased. The differences in PA, MVPA and SB on weekdays and weekends were statistically significant( P <0.01). The proportion of PA and MVPA reaching the recommended amount during the working day of preschool children were 44.9%-59.2%, 45.4%- 61.7%.The proportion reaching the recommended amount of PA and MVPA on weekends were 24.7%-27.8%, 24.5%-29.9%, and the proportion reaching the recommended amount on weekdays was higher than that on weekends. Conclusion There is still gap between actual amount of physical activity and the recommended amount. There are different modes of activity on weekdays and weekends, and weekends are the least active periods. Parents and teachers should pay enough attention to the establishment of "social campus family" model to improve the lack of physical activity of preschool children.

Objective: To investigate the effects of physical activity (PA) intensity and sedentary behavior (SB) on calcanues bone mineral density (BMD) in preschool children, so as to provide a basis for rationalizing the daily physical activity of preschool children to promote bone health. Methods: A total of 673 pre school children aged 3-6 years from nine kindergartens in Pingxiang City, Ganzhou City and Yingtan City of Jiangxi Province, were selected from September to December 2021 by using the whole stratified cluster random sampling method. The PA levels and SB were measured by using a three axis acceleration sensor, and left calcanues BMD was measured by an ultrasound bone densitometer. Multiple linear regression was used to explore the effects of changes in PA on calcanues BMD in pre school children of all ages. Results: Of the 673 preschoolers surveyed, 498 (74.0%) achieved an average of ≥60 min of moderate to vigorous physical activity (MVPA) per day, there were 265 boys (71.2%), and 233 girls ( 77.4 %). The difference between genders was not statistically significant ( χ 2=2.77, P >0.05). There was no statistically significant difference in the BMD test of the calcaneus bones of preschoolers by gender ( Z=0.42, P >0.05). The difference in BMD results of pre school children with 3, 4, 5 to 6 years was statistically significant ( H=2.65, P <0.05). Correlation analysis revealed a negative correlation between SB duration and calcaneus BMD ( r =-0.13), and a positive correlation between low intensity physical activity (LPA) duration, MVPA duration, and calcaneus BMD ( r =0.14, 0.25 ) ( P <0.05). Multivariate linear regression analysis showed that SB duration negatively correlated with calcaneus BMD, whereas LPA and MVPA duration positively correlated with calcaneus BMD ( P <0.05). Conclusions MVPA duration is positively correlated with the growth of BMD in the heel bone and negatively correlated with SB. The kindergartens can adjust their curricula according to the physical and mental developmental characteristics, gender and age differences of pre school children, increase the time of outdoor activities, and reduce the sedentary time to promote the bone health of young children.

Objective: Based on physical activity (PA) and sedentary behavior (SB) variables on weekdays and weekends, the study aims to cluster the physical activities inside and outside kindergartens and to explore the cluster characteristics of different children using physical fitness indicators, so as to provide new strategies and methods for early childhood education and health. Methods: From March to June 2019, 291 children aged 3-6 years from 6 kindergartens in Nanchang were recruited by a stratified cluster random sampling method. The ActiGraph GT3X-BT triaxial accelerometer was used to measure and analyze the PA and SB levels inside and outside the kindergarten. A twostep clustering algorithm model was employed for cluster analysis. Physical fitness were measured and evaluated according to the "National Physical Fitness Measurement Standard Manual (Preschool Section)". Differences in physical fitness among different clusters of children were compared, and the cluster characteristics of different children were analyzed. Results: The clustering algorithm model indicated that based on six indicators, including PA and SB inside the kindergarten on weekdays, and PA and SB outside the kindergarten on both weekdays and weekends, children could be divided into three categories:active inside (high PA, low SB inside), active outside (high PA outside), and inactive (low PA, high SB both inside and outside). The average silhouette coefficient of the model was 0.3, indicating good clustering results. Both the active inside and active outside children showed significantly higher PA inside on weekdays, PA outside on weekdays and weekends, daily low intensity physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) than the inactive children ( F=157.91, 80.79 , 95.86, 95.52, 124.74, P <0.05). After adjusting for gender and age, the physical fitness scores of both active outside ( 19.03 ±0.47) and active inside (19.11±0.40) were significantly higher than those of the inactive children (17.94±0.31). Additionally, active inside children (3.91±0.14) also showed significantly better performance in continuous double-leg jumps, compared to inactive children (3.45±0.11) ( P <0.05). Conclusion Children active inside and those active outside perform well in PA. Future research should focus on the proportion of structured and unstructured PA time to enhance the overall physical fitness of children.

Objective To explore the CRP harmonization by calibration using commutable trueness verification materials. Methods High and low level of CRP concentrations trueness verification materials(H and L) were prepared by Beijing center for clinical laboratories. Thesetrueness verification materials were diluted to 5 calibration points(5L, 4L+1H, 3L+2H, 1L+4H, 5H) by weighing method, respectively. These 5 points were used to calibrate four different brands of CRP detection system (Diasys, Leadman, Siemens and Roche) instead of the original procedure. Sera from 21 patients and the international standard ERM DA-474/IFCC were used to compare harmonization and trueness after calibration. Each sample above was measured twice. Results After calibration, the median of CV was reduced from 19.33％ to 2.92％ among 21 patient samples, less than the optimal CV based on biological variability (CV=10.6％). Compared with Desai, the slopes were closer to 1 from 0.90-1.09 to 0.93-0.96 after calibration. Meanwhile, if ERM-DA474/IFCC was used as the trueness verification materials, the absolute bias wasreduced from 3.08-11.07 mg/L to 0.52-2.97 mg/L which was close to theuncertainty of itself (2.5 mg/L). Conclusions Afterthe calibration which contained five linear concentration points of CRP trueness verification materials by weighing method, both harmonization and trueness of CRP were improved.

Objective To prepare the trueness verification materials of C-reactive protein (CRP) and evaluate its homogeneity, stability and commutability. Methods The high and low CRP concentrations trueness verification materials were from patient leftover sera which were pooled, mixed thoroughly, filtered and aliquoted. The homogeneity, stability and commutability of these materials were evaluated according to CNAS(China National Accreditation Service for Conformity Assessment, CNAS)-GL29:2010 "Reference materials-General and statistical principles for certification (ISO Guide35:2006)"and the Clinical and Laboratory Standards Institute (CLSI) EP30A. The trueness verification materials were used to evaluate the commutability in 10 clinical CRP detection systems, using forty-five patients' leftover sera with different CRP concentration evaluated by Deming regression in EP30A of CLSI. Meanwhile, the commutability of dilution series of ERM DA-474/IFCC were evaluated using the same method. Results A total of two CRP concentration level trueness verification materials were prepared, with high and low concentration levels of 754 and 743 vials, 1 ml each, respectively. The preparation showed good homogeneity (F

Objective To value C-reactive protein ( CRP ) trueness verification materials and to perform the CRP trueness verification program in Beijing .Methods The CRP value of trueness verification materials were assigned by the international reference material ERM DA-474/IFCC, using 10 clinical routine detection systems at departments of clinical laboratory of Beijing Chaoyang and Luhe Hospital Affiliated to Capital Medical University .The calibration curves with 4 ERM DA-474/IFCC dilutions were established and used for value transfer for trueness verification materials of two levels .The uncertainty was also assessed during the process.Then, the trueness verification was performed in the EQA at Beijing Center for Clinical Laboratories ( BCCL ) among 42 clinical laboratories.The samples were distributed according to BCCL standard operating procedure .The Microsoft Excel 2007 and SPSS 17.0 were used to process the results and the function of efficiency ( En) was calculated to verify the difference between the value and the overall mean of all participating laboratories .Results The values and uncertainties of two trueness verification materials of CRP were (109.9 ±9.4) mg/L and (27.1 ±2.4) mg/L respectively.The results of trial application of two level trueness verification materials in the EQA at Beijing Center for Clinical Laboratories (BCCL) were satisfied.There were no significant difference between the transfer values from our study and the values from means of all laboratories in Beijing .The function of efficiency ( En ) was less than 1.Conclusions The valueswhich were established by using multiple detection platforms for CRP trueness verification materialswere accurate and the uncertainties were small .This method is a preferably method for CRP value assignment because there was no suitable reference method for CRP measurement till now .Thematerialswere suitable for the trueness verification program for clinical laboratories in Beijing .

Objective To understand the prevalence of thyroid nodules of children lived in different water iodine areas in Cangzhou City. Methods From Oct. 2015 to Jan. 2017, 15 villages were selected as monitoring sites in Cangzhou,two drinking water samples were collected from each survey site(all had centralized water supply), and the water iodine content was determined. A total of 100 children aged 8 to 10 (half male and female) were examined for thyroid nodules, and at least 50 children (half male and half female) were selected to detect urinary iodine content. In the high iodine water counties, the monitoring sites of iodine salt was according to "National Iodine Deficiency Monitoring Program"; in the monitoring sites of iodine salt supplied counties, students in the monitored village were asked to detect urinary iodine and household salt samples were collected to monitor salt iodine. In the high iodine area, the salt iodine test was carried out by semi-quantitative method. In the non-high iodine area, the salt iodine content of the iodized salt monitoring sites was determined by direct titration, the salt iodine content of Chuan salt and other intensified edible salt was tested by arbitration(GB/T 13025.7-2012). Water iodine and urinary iodine were tested by arsenic and cerium catalytic spectrophotometry. Results Water iodine content was 28.2 - 1 128.0 μg/L in 15 villages; a total of 1 066 urine samples were examined, the median of uriary iodine in each village was 102.6-1 162.0 μg/L;a total of 1 575 children aged 8 to 10 years were examined,among them,125 cases of thyroid nodules were detected; thyroid nodules detection rate was 7.9%. The prevalence of male was 7.0% (61/871), and the prevalence of female was 9.1% (64/704), there was no significant difference in the detection rate of thyroid nodules between different sex (χ2=2.07,P>0.05); The detection rate of thyroid nodules were 4.5%(23/508),7.8%(4/51), 11.6%(59/507)in children with urinary iodine at the appropriate level (100 - <200 μg/L), the appropriate level (200 - < 300 μg/L) and iodine excess level (≥300 μg/L), the difference of thyroid nodules in children with different levels of urinary iodine detection rate was statistically significant (χ2=17.30, P < 0.01). The difference of prevalence of thyroid nodules in children aged 8 to 10 years with water iodine concentrations of 10 - < 100, 100 - < 300 and ≥300 μg/L was statistically significant[2.9%(13/448),7.9%(25/317), 10.7%(87/810),χ2=23.86,P<0.05].The patients with unilateral thyroid nodule accounted for 64.8% (81/125); the patients with multiple thyroid nodules counted for 58.4% (73/125), and 34.2%(13/38),69.0%(60/87)in areas with iodine content less than 300 μg/L and no less than 300 μg/L,the difference between the two was statistically significant (χ2= 13.14, P < 0.01). A total of 1 800 salt samples were collected from the high water iodine counties,of which 1 779 were iodine-free salt, the rate of iodine-free salt was 98.8%; a total of 190 salt samples were collected in student family, in the 4 iodized salt monitoring sites, the salt iodine median of resident's edible salt was 0.0 mg/kg. Conclusion The prevalence of thyroid nodules in children aged 8 - 10 years may be related to high water iodine in Cangzhou City; children with multiple thyroid nodules is also significantly higher in water iodine content greater than 300 μg/L areas.

Objective To understand the prevalence of goiter and nodule as well as the iodine nutritional status of 8 to 10 years old children after changing water source with lower iodine so as to evaluate its intervention effectiveness.Methods From 2014 to 2017,Machang Village and Liangzhang Village of Haixing County in Haixing County were selected as monitoring sites in the water-sourced high iodine area in Hebei Province.Using the cross-sectional survey method,100 children aged 8 to 10 years old were randomly selected in each village,half male and half female.Dynamic monitoring of drinking water iodine content,children's prevalence of goiter and nodule as well as urinary iodine content were conducted before and 1-3 years after changing water resource.Iodine detection was performed using an arsenic cerium-catalyzed spectrophotometric method suitable for iodine-deficient and high-iodine areas (recommended method for national iodine deficiency disease reference experiment);urinary iodine was detected by arsenic cerium catalytic spectrophotometry (WS/T 107-2006).The thyroid test was performed using the B-ultrasound method and the criterion was based on the "Diagnostic Criteria for Endemic Goiter" (WS 276-2007).Results The median iodine content of water in the two villages before the reformation was 861.0 μg/L,and it was 71.6,29.1 and 30.4 μg/L in 1-3 years after water was changed.The overall difference before and after water change was statistically significant (x2 =8.48,P ＜ 0.05).The median urine iodine of children in the two villages before the change of water was 705.0 μg/L,and the median urine iodine of children was 306.0,143.0 and 140.0 μg/L after 1-3 years.The differences were statistically significant (Z =6.56,10.82,11.19,P ＜ 0.05).The goiter rate was 10.3％ (21/203) before changing water,and the goiter rate was 6.3％ (13/205),6.4％ (13/203) and 3.8％ (8/208) in 1-3 years after water exchange,and the difference between before and 3 years after water exchange was statistically significant (x2 =6.61,P ＜ 0.05).Children's nodule prevalence before and 3 years after changing water was 11.3％ (23/203) and 1.4％ (3/208),the difference was statistically significant (x2 =13.42,P ＜ 0.05).Conclusion Three years after changing water resource,children's goiter prevalence is back to normal in general,and nodule prevalence is decreased significantly,which indicates sound intervention effectiveness.