The value of procalcitonin, a novel inflammatory marker, in the diagnosis of myocardial infarction and evaluation of acute coronary syndrome patients.

Background: Procalcitonin is a calcitonin precursor that is used as an inflammatory biomarker in the plasma of patients with sepsis.

Objective: The aim of this study was to determine the diagnostic accuracy of emergency department (ED) point-of-care blood procalcitonin testing in identifying myocardial infarction (MI) in patients with chest pain of presumed ischemic origin.

Methods: Patients over 18 years of age who presented to the ED with MI-typical chest pain of presumed ischemic origin were included in the study. An initial point-of-care blood sample was drawn from each study patient for testing procalcitonin, troponin T, myoglobin, and creatine kinase-MB levels. A second sample was taken 4h after admission for a procalcitonin test. Finally, a 6-h post-admission blood sample was taken to measure troponin T, myoglobin, and creatine kinase-MB levels in each study patient who had an initial negative cardiac marker test.

Results: A total of 1008 patients with chest pain were admitted to the ED during the study period, and a total of 141 patients met study criteria and were entered into the study. ED point-of-care blood procalcitonin testing to identify myocardial infarction in patients with chest pain of presumed ischemic origin had a sensitivity of 38.3% (95% confidence interval [CI] 28.8-47.3%) and a specificity of 77.8% (95% CI 70.0-84.4%), a positive likelihood ratio (LR+) of 1.725 and a negative likelihood ratio (LR-) of 0.792. The 4th hour diagnostic values (sensitivity, specificity, LR+ and LR-) of procalcitonin semi-quantitative (PCT-Q) testing were 90% (95% CI 80.9-95.7%), 59.3% (95% CI 52.5-63.5%), 2.2, and 0.16, respectively.

Conclusion: ED point-of-care testing for procalcitonin had poor diagnostic accuracy for predicting myocardial infarction.