Point-of-care testing for sensitive cardiac troponin Ⅰ in early diagnosis of acute myocardial infarction / 中华急诊医学杂志

ABSTRACT

Objective To evaluate the diagnostic performance of a point-of-care testing for sensitive cardiac troponin Ⅰ (POCT-cTnI) in early diagnosis of chest pain patients who had a high pretest probability of acute myocardial infarction (AMI).Methods Total of 127 patients with new-onset chest pain at the emergency department were enrolled.Blood samples were drawn for the routine blood test,and determined POCT-cTnI and central laboratory testing for high sensitive cardiac troponin T (CLT-hscTnT) at admission,three and then at six hours after admission.All patients were divided into AMI group and non-AMI group according to the final diagnosis,which was adjudicated independently by two physicians who reviewed all available medical records for the 90-day follow-up period,and they were unaware of the results of the investigational assays of cardiac troponins.The receiver operating characteristic (ROC) curves were constructed to assess and compare the diagnostic performance of AMI of two cardiac troponin assays.The comparison of areas under the ROC curves (AUC) was performed by DeLong test,and the sensitivity,specificity,negative predictive values (NPV) and positive predictive values (PPV) for the target markers were calculated by applying a maker-specific cutoff value.Results The final diagnosis of AMI was made in 40 of 127 patients (31.5 ％).The diagnostic accuracy of the two assays oBtained at presentation,as quantified by AUC,was no statistically differences (AUC for POCT-cTnⅠ,0.901,95％ CI,0.901 to 0.947;and for CLT-hscTnT,0.907,95％ CI,0.842 to 0.951;Z =0.235,P =0.745).The AUC for POCT-cTnI at 3 hours after admission was significantly higher than that on admission (0.931 vs.0.858;Z =-2.038,P =0.042),while there was on further improvement at 6 hours after admission (0.931 vs.0.949;Z =-1.435,P =0.151).With use of POCT-cTnI (cutoff value 0.023 ng/mL,which was the 99th percentile upper reference limit) on adimission,the clinical sensitivity was 77.5％,and the specificity was 94.2％.A single sample of POCT-cTnI at 3 hours after admission improved the diagnostic accuracy,with a sensitivity of 96.4％,a specificity of 92.0％,and a NPV of 98.6％,a PPV of 81.8％.While,with use of CLT-hscTnT (cutoff value 0.014 ng/mL,was the 99th percentile upper reference limit) at 3 hours after admission,the NPV reached to 100％.Conclusions The use of a POCT-cTnI assay in chest pain patients can identify and exclude the AMI rapidly and exactly at three hours after admission,and the diagnostic performance is equivalent to CLT-hscTnT.