Establishment Of Reference Intervals For Myocardial Enzyme Activity And Lipids Among Healthy Population Aged 1?<18 Years Old In Jilin Province

Background and objectives:Medical assessment depends on reference interval.Establishing a reliable reference interval is an important task for clinical laboratories regarding,involving multiple factors as age,gender,region,methodology and others.There are no feasible pediatric reference intervals in most laboratory indicators so far in China,thus those applied among different-leveled clinical laboratories source variously.The International Federation of Clinical Chemistry and Laboratory Medicine(IFCC)and the Clinical & Laboratory Standards Institute(CLSI)have released EP28-A3 C guideline,in which questions were answered in detail and a standard procedure was established.Indicators of myocardial enzyme activity are commonly used for screening and diagnosis of cardiovascular diseases,including aspartate amino transferase(AST),lactate dehydrogenase(LDH),creatine kinase(CK)and creatine kinase-MB(CKMB).In addition,triglyceride(TG),cholesterol(CHOL),high density lipoprotein cholesterol(HDL-C)and low density lipoprotein cholesterol(LDL-C)are contributing factors of cardiovascular events.This study followed the EP28-A3 C guideline,in which a large number of healthy children and adolescents were recruited across Jilin Province with a large database established after rigorous evaluation.VITROS 5600 Integrated system was used.Reference intervals of AST,LDH,CK,and CKMB activities and TG,CHOL,HDL-C,and LDL-C concentrations were established in Jilin Province,China.Fisher's optimal segmentation method was applied with 4 indicatorsof myocardial enzyme activity to assess cardiac developmentof children and adolescents.Methods:Reference individuals were recruited among 5 administrative regions in Jilin Province.Questionnaires were issued for screening,and then health status of subjects was evaluated by pediatricians in clinic.A total of 6322 reference individuals were selected,ranging from 1~<18 years old.VITROS 5600 Integrated System and auxiliary reagents were applied to test serum myocardial enzyme activity and lipid concentration,with quality control performed to ensure accurate results.After data recheck and cleaning,partitioning was performed on statistical description and sample size as well as the confidence interval(CI)was calculated.An ordered sample was constructed using average or median of AST,LDH,CK,and CKMB from per 1-year-old subgroups,and trends of myocardial enzyme activity were obtained using the Fisher optimal segmentation method.Results:(1)A total of 6,322 individuals(3203 females and 3119 males)were included in this study,with a sex ratio of 1: 1.03.(2)AST decreased rapidly during 1~<4 years old,then fluctuated during 11~<18 years old;CK showed gender difference at the age of 11 years old;LDH and CKMB activity presented downward trends;TG descended during 1~<11 years;CHOL and LDL-C were quite stable generally;HDL-C showed an upward trend during 1~<11 years old before stabilized.(3)Except that CK activtity was unrelated to age,the correlation between indicators of myocardial enzyme activity with age and gender is significant;TG,HDL-C were correlative to age while CHOL,LDL-C showed correlation with gender.Myocardial enzyme activity interrelated closely,while correlation between indicators of myocardial enzyme activity and indexes of lipid concentrations were not close.(4)Intervals of lipid concentration could be shared among people aged 1~<18 years old whereas reference intervals of myocardial enzyme activity were stratified according to age and gender.(5)Intervals of this study were different from results of similar researches domestically and abroad.(6)Trends of myocardial enzyme activity in males and females calculated by Fisher's optimal segmentation method respectively was discrepant.Conclusion:(1)As children and adolescents grow,activity of AST,LDH,and CKMB decreases,while activity of CK,concentration of TG,CHOL,LDL-C,and HDL-C are generally stable.(2)Activity of myocardial enzyme relates to age and gender;TG and HDL-C are related to age as CHOL and LDL-C are related to gender.(3)Indicators of myocardial enzyme activityare significantly correlated.(4)Reference intervals established in the study are different from results of adults,children and adolescents domestically and abroad.