Evaluation of a rapid bedside assay for detection of serum cardiac troponin T

Abstract

Objective: To evaluate a rapid, qualitative, bedside immunoassay for cardiac-specific troponin T (cTnT) using a handheld device containing monoclonal antibodies.

Design: Comparison of rapid cTnT assay with clinical standard for diagnosis of myocardial infarction (MI).

Setting: Tertiary care university medical center.

Patients: A cohort of 100 patients admitted for evaluation of chest pain who had sufficient blood samples at presentation for measurement of creatine kinase, creatine kinase MB fraction, and rapid cTnT as well as adequate clinical data to establish the diagnosis of MI.

Intervention: None; treating physicians were blinded to rapid cTnT results.

Main outcome measures: Sensitivity and specificity of rapid cTnT assay for MI; likelihood ratios of positive and negative rapid cTnT assay results; relative risk (RR) for serious cardiac events with positive rapid cTnT assay result on admission.

Results: Sensitivity of the rapid cTnT assay increased from 33% within 2 hours from the onset of chest pain to 86% after 8 hours (P < .001); specificity ranged from 86% to 100% during the same time intervals. The odds of an MI increased sixfold with a positive assay result within 2 hours of chest pain and decreased sixfold with a negative assay result after 8 hours. The RR for experiencing death or nonfatal MI was 6.8 for patients presenting with a positive rapid cTnT assay.

Conclusions: The rapid cTnT assay is a simple, efficient test that for the first time provides clinicians with a useful laboratory tool for point-of-care evaluation of patients with chest pain.