Evaluation of the analytical performance of AccuTnI+3 assay and establishment of the regional 99th percentile from an apparently healthy Chinese population / 中华检验医学杂志

ABSTRACT

Objective To validate the analytical performance of a cardiac troponin I(cTnI)assay AccuTnI+3 on chemiluminescnet analyzer DXI800 and Access2;and to establish the 99th percentile of cTnI in an apparently healthy Chinese population.Methods The subjects are composed of 1 369 apparently healthy people and 20 acute myocardial infarction(AMI)patients from Wuhan Asian Heart Hospital and Fuwai Hospital from October 2014 to June 2015.The healthy people include 680 males and 689 females;with 340 subjects aged 18-30,674 subjects aged 31-64, and 355 subjects aged ≥65.The detection limits and imprecision of AccuTnI +3 assays were validated according to CLSI EP 15-A2 and EP17-A2 documents;the same samples were analyzed on DXI800 and Access2 to assess the consistency between the two analyzers using Bland Altman plot and Passing-Bablok regression.The correlation between different sample types (lithium heparin plasma, EDTA plasma & serum)were assessed using linear regression analysis.The lithium heparin plasmasamples from 1 369 apparently healthy people were analyzed to calculate the 99th percentile of cTnI.The cTnI concentrations were compared among age and sex groups.The 99th percentile of cTnI were also calculated for each group.The detection rate of cTnI in apparently healthy people was calculated using SPSS23.0.Results The limit of blank(LoB), limit of detection(LoD), and limit of quantification(LoQ)where CV%=10% were 0.007 ng/ml,0.010 ng/ml and 0.016 ng/ml on DXI800;0.008 ng/ml,0.012 ng/ml and 0.026 ng/ml on Access2,respectively.The cTnI measurements on DXI800 and Access2 were consistent and comparable.The cTnI concentrations of lithium heparin plasma, EDTA plasma and serum samples were linearly correlated pairwise EDTA plasma measuremen t =0.76 heparin plasma measurement, R2=0.999(n=40, P<0.001); serum measuremen t =1.05 heparin plasma measurement,R2=0.996(n=40,P<0.001); serum measuremen t=1.38 EDTA plasma measurement, R2=0.993(n=40,P<0.001).The 99th percentiles were 0.030 ng/ml and 0.035 ng/ml on DXI800 and Access2,respectively,from 1 369 apparently healthy Chinese people.cTnI is significantly higher in elder group than in younger group.The 99th percentiles in 18-30 years old group,31-64 years old group,and≥65 years old group are0.011 ng/ml,0.029 ng/ml,and 0.035 ng/ml respectively for DXI800;0.023 ng/ml,0.034 ng/ml, and 0.045 ng/ml respectively for Access2.cTnI is significantly higher in men than in women.The 99th percentiles in men and women are 0.034 ng/ml and 0.032 ng/ml respectively for DXI800;0.043 ng/ml and 0.031 ng/ml respectively for Access2.cTnI was measurable in 62%and 87%of healthy subjects on DXI800 and Access2 systems,respectively.Conclusions The analytical performance of AccuTnI+3 assay fulfills the need of clinical use and the criteria of high-sensitive cardiac troponin assay.