Objective:to investigate age-related changes in high-sensitivity cardiac troponin T(hs-cTnT)levels among middle-aged and elderly individuals, and to establish reference values for the 99th percentile upper reference limit(99th URL)of hs-cTnT within this demographic.Methods:This research is designed as a cross-sectional study.Hs-cTnT test results were collected from outpatients at Beijing Hospital between January 2018 and December 2023.The final sample included 5, 677 outpatients aged 45 to 85 years(65±10), all of whom were free from cardiovascular diseases and other chronic heart-related conditions.Multiple linear regression was utilized to assess the impact of gender and age group on hs-cTnT concentrations within the middle-aged and elderly populations.Furthermore, a generalized additive model for location, scale, and shape(GAMLSS)was employed to generate percentile curves of hs-cTnT by gender in this cohort, with the aim of determining the 99th URLs for both middle-aged and elderly individuals.Results:Multiple linear regression analyses indicated that both gender and age significantly influenced hs-cTnT levels in middle-aged and elderly populations( β60-69 years=1.399, β≥70 years=5.306, βgender=-2.650, all Pvalues<0.001).The hs-cTnT data for both males and females conformed to Box-Cox-Cole-Green(BCCG)distributions, with percentile curves fitted at the 25th, 50th, 75th, and 99th percentiles according to gender.The percentile values of hs-cTnT in both males and females demonstrated a progressive increase with advancing age.Notably, males exhibited higher 99th percentile values than females across all age groups. Conclusions:The GAMLSS approach is employed to establish continuous reference intervals for hs-cTnT in the middle-aged and elderly population.This effort aims to provide a theoretical foundation for reference values specific to this demographic in China and to offer guidance for clinical diagnosis and treatment.

Objective:To analyze the quality level of maternal mid-trimester serum prenatal screening in China from 2019 to 2023.Methods:A questionnaire survey was conducted to collect information from laboratories participating in the National Health Commission′s Clinical Laboratory Center inter-laboratory quality assessment program for prenatal screening from 2019 to 2023. The collected data included screening protocols, detection methods, testing systems, and monthly laboratory screening quality indicators. The Chi-square test was used to compare the initial screening positive rates among different screening protocols, provinces, detection methods, and testing systems. A log-transformed linear regression analysis was performed to evaluate the relationship between the average annual sample size and the out-of-control rate of various median multiple of the median (mMoM) values.Results:This study included 806 laboratories from 29 provinces (including autonomous regions and municipalities). The five-year average out-of-control rates for mMoM values across indicators ranged from 15.8% to 31.3%. The initial positive rates of dual, triple, and quadruple screening protocols were statistically different ( χ2=760.2, P<0.001). The initial positive rates across different provinces ranged from 4.7% to 10.3%, with statistically significant differences ( χ2=35 388.0, P<0.001). There were also statistically significant differences in initial positive rates between different testing systems ( χ2=2 493.2, P<0.001). Testing systems using chemiluminescence methods had significantly higher initial positive rates compared to systems using time-resolved fluorescence methods (7.2% vs. 6.5%, χ2=533.6, P<0.001). Log-linear regression analysis showed that testing systems with larger annual average sample sizes had lower out-of-control rates for mMoM values (AFP: β=-0.100, P=0.005; hCG: β=-0.123, P=0.008; uE3: β=-0.139, P=0.007). Conclusion:There are significant differences in the quality of maternal mid-trimester serum screening across different detection methods, testing systems and provinces in China.

Objective:To evaluate the sample preparation proficiency and storage proficiency of 11 clinical biobanks in Beijing through simulated experiments, and to establish an assessment method for the quality comparability of biological samples.Methods:An exploratory research design was adopted. In November 2023, artificial composite serum quality control materials containing six recombinant human protein markers—recombinant human alanine aminotransferase (rhALT), recombinant human aspartate aminotransferase (rhAST), recombinant human creatine kinase (rhCK), recombinant human creatine kinase-MB (rhCK-MB), recombinant human B-type natriuretic peptide (rhBNP), and recombinant human troponin I (rhTNI)—were distributed to 11 clinical biobanks in Beijing City. Sample preparation and storage followed the standardized operating procedures. Proficiency differences were assessed through statistical analysis.Results:Three-way repeated measures ANOVA revealed all six protein markers showed a declining trend over storage time in ultra-low-temperature environments ( F values 11.68-4 179.66, all P<0.01). However, neither long-term/temporary refrigerator types ( F values 0.01-1.23, all P>0.05)nor placement locations within refrigerators significantly affected the stability of these six proteins ( F valus 0.03-1.47, all P>0.05). The biases in detection results for rhALT, rhAST, rhTNI, and rhBNP at different storage time points were within the allowable bias limits for each item, supporting their use as markers for protein stability in biobank samples. All 11 institutions passed the storage proficiency assessment. In the preparation proficiency assessment, deviations were observed in post-preparation sample results, with a notably high out-of-control rate for rhCK (36.36%). Conclusion:Sample preparation proficiency can serve as a quality control metric for clinical biobanks. Future external quality assessment systems for biobanks should focus on sample preparation rather than storage processes.

Objective:To analyze the quality level of maternal mid-trimester serum prenatal screening in China from 2019 to 2023.Methods:A questionnaire survey was conducted to collect information from laboratories participating in the National Health Commission′s Clinical Laboratory Center inter-laboratory quality assessment program for prenatal screening from 2019 to 2023. The collected data included screening protocols, detection methods, testing systems, and monthly laboratory screening quality indicators. The Chi-square test was used to compare the initial screening positive rates among different screening protocols, provinces, detection methods, and testing systems. A log-transformed linear regression analysis was performed to evaluate the relationship between the average annual sample size and the out-of-control rate of various median multiple of the median (mMoM) values.Results:This study included 806 laboratories from 29 provinces (including autonomous regions and municipalities). The five-year average out-of-control rates for mMoM values across indicators ranged from 15.8% to 31.3%. The initial positive rates of dual, triple, and quadruple screening protocols were statistically different ( χ2=760.2, P<0.001). The initial positive rates across different provinces ranged from 4.7% to 10.3%, with statistically significant differences ( χ2=35 388.0, P<0.001). There were also statistically significant differences in initial positive rates between different testing systems ( χ2=2 493.2, P<0.001). Testing systems using chemiluminescence methods had significantly higher initial positive rates compared to systems using time-resolved fluorescence methods (7.2% vs. 6.5%, χ2=533.6, P<0.001). Log-linear regression analysis showed that testing systems with larger annual average sample sizes had lower out-of-control rates for mMoM values (AFP: β=-0.100, P=0.005; hCG: β=-0.123, P=0.008; uE3: β=-0.139, P=0.007). Conclusion:There are significant differences in the quality of maternal mid-trimester serum screening across different detection methods, testing systems and provinces in China.

Objective:To evaluate the sample preparation proficiency and storage proficiency of 11 clinical biobanks in Beijing through simulated experiments, and to establish an assessment method for the quality comparability of biological samples.Methods:An exploratory research design was adopted. In November 2023, artificial composite serum quality control materials containing six recombinant human protein markers—recombinant human alanine aminotransferase (rhALT), recombinant human aspartate aminotransferase (rhAST), recombinant human creatine kinase (rhCK), recombinant human creatine kinase-MB (rhCK-MB), recombinant human B-type natriuretic peptide (rhBNP), and recombinant human troponin I (rhTNI)—were distributed to 11 clinical biobanks in Beijing City. Sample preparation and storage followed the standardized operating procedures. Proficiency differences were assessed through statistical analysis.Results:Three-way repeated measures ANOVA revealed all six protein markers showed a declining trend over storage time in ultra-low-temperature environments ( F values 11.68-4 179.66, all P<0.01). However, neither long-term/temporary refrigerator types ( F values 0.01-1.23, all P>0.05)nor placement locations within refrigerators significantly affected the stability of these six proteins ( F valus 0.03-1.47, all P>0.05). The biases in detection results for rhALT, rhAST, rhTNI, and rhBNP at different storage time points were within the allowable bias limits for each item, supporting their use as markers for protein stability in biobank samples. All 11 institutions passed the storage proficiency assessment. In the preparation proficiency assessment, deviations were observed in post-preparation sample results, with a notably high out-of-control rate for rhCK (36.36%). Conclusion:Sample preparation proficiency can serve as a quality control metric for clinical biobanks. Future external quality assessment systems for biobanks should focus on sample preparation rather than storage processes.

Objective:to investigate age-related changes in high-sensitivity cardiac troponin T(hs-cTnT)levels among middle-aged and elderly individuals, and to establish reference values for the 99th percentile upper reference limit(99th URL)of hs-cTnT within this demographic.Methods:This research is designed as a cross-sectional study.Hs-cTnT test results were collected from outpatients at Beijing Hospital between January 2018 and December 2023.The final sample included 5, 677 outpatients aged 45 to 85 years(65±10), all of whom were free from cardiovascular diseases and other chronic heart-related conditions.Multiple linear regression was utilized to assess the impact of gender and age group on hs-cTnT concentrations within the middle-aged and elderly populations.Furthermore, a generalized additive model for location, scale, and shape(GAMLSS)was employed to generate percentile curves of hs-cTnT by gender in this cohort, with the aim of determining the 99th URLs for both middle-aged and elderly individuals.Results:Multiple linear regression analyses indicated that both gender and age significantly influenced hs-cTnT levels in middle-aged and elderly populations( β60-69 years=1.399, β≥70 years=5.306, βgender=-2.650, all Pvalues<0.001).The hs-cTnT data for both males and females conformed to Box-Cox-Cole-Green(BCCG)distributions, with percentile curves fitted at the 25th, 50th, 75th, and 99th percentiles according to gender.The percentile values of hs-cTnT in both males and females demonstrated a progressive increase with advancing age.Notably, males exhibited higher 99th percentile values than females across all age groups. Conclusions:The GAMLSS approach is employed to establish continuous reference intervals for hs-cTnT in the middle-aged and elderly population.This effort aims to provide a theoretical foundation for reference values specific to this demographic in China and to offer guidance for clinical diagnosis and treatment.

Background: Clinical chemistry tests are most widely used in clinical laboratories, and diverse measurement systems for these analyses are available in China. We evaluated the imprecision of clinical chemistry measurement systems based on internal QC (IQC) data. Methods: IQC data for 27 general chemistry analytes were collected in February each year from 2013 to 2022. Four performance specifications were used to calculate pass rates for CVs of IQC data in 2022. Boxplots were drawn to analyze trends of CVs, and differences in CVs among different groups were assessed using the Mann–Whitney U-test or Kruskal– Wallis test. Results: The number of participating laboratories increased significantly from 1,777 in 2013 to 5,425 in 2022. CVs significantly decreased for all 27 analytes, except creatine kinase and lipase. Triglycerides, total bilirubin, direct bilirubin, iron, and γ-glutamyl transferase achieved pass rates > 80% for all goals. Nine analytes with pass rates < 80% based on 1/3 allowable total error were further analyzed; the results indicated that closed systems exhibited lower CVs than open systems for all analytes, except total protein. For all nine analytes, differences were significant between tertiary hospitals and non-tertiary hospitals and between accredited and non-accredited laboratories. Conclusions The CVs of IQC data for clinical chemistry have seen a continuous overall improvement in China. However, there is ample room for imprecision improvement for several analytes, with stricter performance specifications.

Objective: To analyze the characteristics of influenza virus detection in an influenza outbreak in schools, so as to provide a strategic basis for the treatment of influenza outbreaks in schools. Methods: A total of 1 702 samples were collected from 52 school influenza outbreaks reported in Linyi City in 2021-2022. The samples were divided into 3 types according to different symptoms during the management of the epidemic [group A:influenzalike illness (ILI) group; group B:mild illness group; group C:close contacts group]. Rt-PCR was used to detect influenza virus nucleic acid in the collected samples. The detection rate of influenza virus in the outbreaks was analyzed by χ2 test. Results: In total, 1 071 samples (62.93%) tested positive for influenza virus nucleic acid. Among them, 610 out of 726 samples (84.02%) were detected in group A, while 331 out of 634 samples (52.21%) were detected in group B. In group C, 130 out of 342 samples (38.01%) tested positive. The differences were statistically significant (χ2=260.71, P<0.01). In group A, males had a detection rate of 80.83% for influenza virus nucleic acid, compared to 91.36% for females. For group B, the rates were 53.31% for males and 50.87% for females. In group C, males had a rate of 30.72%, while females had a rate of 43.92%. Statistical significance for gender differences was observed only in groups A and C (χ2=12.67, 6.25, P<0.05). According to the days of onset, the detection rates of influenza virus nucleic acid among patients with onset 0-6 days were 56.30%, 74.49%, 89.35%, 86.23%, 69.67%, 62.75%, 34.33%, respectively, and the difference was statistically significant (χ2=128.27, P<0.01). Conclusions Mild cases and close contacts are likely key factors contributing to the prolonged emergence of new cases within classrooms during school influenza outbreaks. The progression of influenza symptoms is related to the risk of transmission.

To analyze the changes in lactate dehydrogenase, creatine kinase, creatine kinase isoenzyme, high-sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, homocysteine, and novel inflammatory indices (neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, systemic immune-inflammation index) before and after competitions in amateur marathon runners, and to assess the effects of myocardial injury due to acute exercise and the value of novel inflammatory indices in marathon exercise monitoring. This paper is an analytical study. Amateur athletes recruited by Beijing Hospital to participate in the 2022 Beijing Marathon and the 2023 Tianjin Marathon, and those who underwent health checkups at the Beijing Hospital Medical Checkup Center from January to June 2023 were selected as the study subjects, and 65 amateur marathon runners (41 males and 24 females) and 130 healthy controls (82 males and 48 females) were enrolled in the study according to the inclusion criteria. Peripheral blood was collected one week before, immediately after, and one week after running, and routine blood tests, cardiac enzymes, infarction markers, N-terminal B-type natriuretic peptide precursor, and homocysteine were performed to calculate the values of novel inflammatory indexes. Wilcoxon signed-rank test and Spearman′s rank correlation analysis were used to compare the differences in the levels of each index between the amateur marathon population and the health checkup population, and to compare the changes and correlations of each index at the three time points in the amateur marathoners.The results showed that the neutrophil-lymphocyte ratios of the healthy physical examination population and 65 amateur marathoners 1 week before running were 1.73 (1.33, 2.16) and 1.67 (1.21, 2.16), the platelet-lymphocyte ratios were 122.75 (96.69, 155.89) and 120.86 (100.74, 154.63), and the systemic immune inflammation index was 398.62 (274.50, 538.69) and 338.41 (258.62, 485.38), etc.; on 1 week before running, immediately after running and 1 week after running, lactate dehydrogenase of 65 amateur marathon runners was 173.00(159.00, 196.50)U/L,284.00(237.50, 310.50)U/L, 183.00(165.50, 206.50)U/L, creatine kinase was 131.00(94.30, 188.20)U/L,318.00(212.00, 573.15)U/L,139.00(90.55, 202.40)U/L, creatine kinase isoenzyme was 2.50(1.76, 3.43)μg/L,6.24(4.87, 10.30)μg/L,2.73(1.57, 4.40)μg/L.In 65 amateur marathon runners, lactate dehydrogenase, creatine kinase, creatine kinase isoenzyme, high sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, homocysteine, and novel inflammation markers were significantly elevated in the immediate post-run period compared with 1 week before the run, and the differences were statistically significant ( Z=-7.009, Z=-6.813, Z=-6.885, Z=-7.009, Z=-7.009, Z=-6.656; P<0.05 for the above indicators).Neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and systemic immune-inflammatory index all showed significant positive correlation with the pre-and post-run rates of change of high-sensitivity troponin T ( ρ=0.28, P=0.03; ρ=0.31, P=0.01; ρ=0.27, P=0.03); these 3 markers were also significantly and positively correlated with the pre-and post-run rates of change in a collection of myocardial-related markers such as lactate dehydrogenase, creatine kinase, creatine kinase isozymes, high-sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, and homocysteine, respectively( r=0.446, P=0.039; r=0.452, P=0.033; r=0.449, P=0.036).In addition, the platelet-lymphocyte ratio was positively correlated with the pre-and post-run rates of change in creatine kinase and creatine kinase isoenzymes( ρ=0.27, P=0.03; ρ=0.28, P=0.02).In conclusion, acute myocardial injury may be triggered during marathon exercise. Changes in novel inflammatory markers were significantly associated with changes in myocardial enzymes, infarction markers, N-terminal B-type natriuretic peptide precursors, and homocysteine, which may be of value for the prediction of myocardial injury during exercise.

To analyze the changes in lactate dehydrogenase, creatine kinase, creatine kinase isoenzyme, high-sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, homocysteine, and novel inflammatory indices (neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, systemic immune-inflammation index) before and after competitions in amateur marathon runners, and to assess the effects of myocardial injury due to acute exercise and the value of novel inflammatory indices in marathon exercise monitoring. This paper is an analytical study. Amateur athletes recruited by Beijing Hospital to participate in the 2022 Beijing Marathon and the 2023 Tianjin Marathon, and those who underwent health checkups at the Beijing Hospital Medical Checkup Center from January to June 2023 were selected as the study subjects, and 65 amateur marathon runners (41 males and 24 females) and 130 healthy controls (82 males and 48 females) were enrolled in the study according to the inclusion criteria. Peripheral blood was collected one week before, immediately after, and one week after running, and routine blood tests, cardiac enzymes, infarction markers, N-terminal B-type natriuretic peptide precursor, and homocysteine were performed to calculate the values of novel inflammatory indexes. Wilcoxon signed-rank test and Spearman′s rank correlation analysis were used to compare the differences in the levels of each index between the amateur marathon population and the health checkup population, and to compare the changes and correlations of each index at the three time points in the amateur marathoners.The results showed that the neutrophil-lymphocyte ratios of the healthy physical examination population and 65 amateur marathoners 1 week before running were 1.73 (1.33, 2.16) and 1.67 (1.21, 2.16), the platelet-lymphocyte ratios were 122.75 (96.69, 155.89) and 120.86 (100.74, 154.63), and the systemic immune inflammation index was 398.62 (274.50, 538.69) and 338.41 (258.62, 485.38), etc.; on 1 week before running, immediately after running and 1 week after running, lactate dehydrogenase of 65 amateur marathon runners was 173.00(159.00, 196.50)U/L,284.00(237.50, 310.50)U/L, 183.00(165.50, 206.50)U/L, creatine kinase was 131.00(94.30, 188.20)U/L,318.00(212.00, 573.15)U/L,139.00(90.55, 202.40)U/L, creatine kinase isoenzyme was 2.50(1.76, 3.43)μg/L,6.24(4.87, 10.30)μg/L,2.73(1.57, 4.40)μg/L.In 65 amateur marathon runners, lactate dehydrogenase, creatine kinase, creatine kinase isoenzyme, high sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, homocysteine, and novel inflammation markers were significantly elevated in the immediate post-run period compared with 1 week before the run, and the differences were statistically significant ( Z=-7.009, Z=-6.813, Z=-6.885, Z=-7.009, Z=-7.009, Z=-6.656; P<0.05 for the above indicators).Neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and systemic immune-inflammatory index all showed significant positive correlation with the pre-and post-run rates of change of high-sensitivity troponin T ( ρ=0.28, P=0.03; ρ=0.31, P=0.01; ρ=0.27, P=0.03); these 3 markers were also significantly and positively correlated with the pre-and post-run rates of change in a collection of myocardial-related markers such as lactate dehydrogenase, creatine kinase, creatine kinase isozymes, high-sensitivity troponin T, N-terminal B-type natriuretic peptide precursor, and homocysteine, respectively( r=0.446, P=0.039; r=0.452, P=0.033; r=0.449, P=0.036).In addition, the platelet-lymphocyte ratio was positively correlated with the pre-and post-run rates of change in creatine kinase and creatine kinase isoenzymes( ρ=0.27, P=0.03; ρ=0.28, P=0.02).In conclusion, acute myocardial injury may be triggered during marathon exercise. Changes in novel inflammatory markers were significantly associated with changes in myocardial enzymes, infarction markers, N-terminal B-type natriuretic peptide precursors, and homocysteine, which may be of value for the prediction of myocardial injury during exercise.