A faster detection method for high-sensitivity cardiac troponin-POCT quantum dot fluorescence immunoassay

High-sensitivity cardiac troponin (hs-cTn) is a significant biomarker of myocardial injury and necrosis, and has momentous clinical significance for the diagnosis and risk stratification of acute myocardial infarction (AMI). The purpose of this study is to determine the accuracy and sensitivity of hs-cTn detection in whole blood samples with a new faster method-Point of Care Testing (POCT) quantum dot fluorescence immunoassay.

Blood samples from 415 patients with chest pain suggestive of AMI from August to November 2017 in The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University were analyzed. We first performed hs-cTnI test with anticoagulated whole blood by POCT quantum dot fluorescence immunoassay. After the sample was centrifuged, the plasma sample was taken for detection of hs-cTnT by electrochemiluminescence immunoassay. The final diagnosis was determined by two independent cardiologists.

Firstly, by measuring the receiver operating characteristic curve (ROC curve) and the area under the curve (AUC) of 32 patients with AMI, it was found that the measurement accuracy of the POCT quantum dot fluorescence immunoassay was relative high (AUC was 0.866, 95% confidence interval is 0.783 to 0.949). There was no statistical difference between POCT quantum dot fluorescence immunoassay and electrochemiluminescence troponin assay [Z value =1.527, P value =(0.063, 0.064)]. In addition, the study also calculated the performance evaluation index of POCT quantum dot fluorescence immunoassay (critical value 0.04 ng/mL) and analyzed the ROC curve to compare the diagnostic accuracy of both for cardiogenic diseases and the diagnostic efficacy of patients with AMI. Our study found that the new method-POCT quantum dot fluorescence immunoassay had high diagnostic efficiency, which was similar to the traditional electrochemiluminescence method.

The measurements of hs-cTn by the method of Vazyme POCT quantum dot immunofluorescence and Roche electrochemiluminescence method have a good correlation (Y=37.419+131.009X, r=0.935), and also have a good consistency in the diagnosis of AMI. In addition, compared with the traditional electrochemiluminescence method, quantum dot immunofluorescence is faster and more suitable for clinical needs.