The of troponin in patients with acute coronary

The effectiveness of point-of-care testing for the detection of
troponin in patients with acute coronary syndromes

Ozturk Ayse1

1University College Leuven-Limburg (HERESTRAAT
49, 3000 LEUVEN, BELGIUM)

Summary

Background. Acute coronary syndrome (ACS) encompasses the
spectrum from unstable angina to non-ST-segment elevation myocardial infraction
(STEMI) and non-ST-segment elevation myocardial infraction (NSTEMI). 2 These
conditions can be triggered by several causes, mainly because of atherosclerosis
and thrombosis, where the blood flow to the heart muscle is decreased. 1 The
symptoms prompting the suspicion of ACS include chest pain, neck or arm
discomfort, dyspnea, epigastric pain,… 8

ACS is a
medical emergency that requires quick diagnosis and therapy. 3 Patients with STEMI
show an elevated ST-segment on an electrocardiogram (ECG). Others show no
ST-elevation and are mainly diagnosed with unstable angina or NSTEMI. The
distinction between unstable angina and NSTEMI is based on the finding of
elevated cardiac markers. 6

Troponin is
composed by three peptides: troponin T (TnT), a regulatory protein to
tropomyosin; troponin I (TnI), an inhibitor of actomyosin ATPase activity; and
troponin C (TnC), the calcium-binding subunit of the troponin complex. Different
isoforms are found in cardiac and skeletal muscle for both TnT and TnI. The
cardiac forms are called cardiac TnT (cTnT) and cardiac TnI (cTnI). Increased amounts
of troponins are released into the bloodstream when an damage is done to the
myocardium. After a myocardial infraction, cTnI and cTnT begin to increase and
stay elevated for a few days. These parameters can be measured by point-of-care
testing (POCT). 1, 4, 5

Different studies have reviewed the use of POCT for the detection of troponin
and concluded that this method has lots of advantages: first of all, rapid test
results are obtained by reducing the time spent in test ordering, specimen transport
to a laboratory and data processing. Therefore diagnosis and treatment can be implemented
slightly earlier. Secondly, there have been documented improvements such as
decreased emergency room (ER) and hospital length-of-stay (LOS), decreased
overall cost following these technologies. 1, 4, 5, 6, 7, 8

Although all consulted articles share the same opinion on the advantages
of POCT for the detection of troponin, the opinion on its effectiveness in the
diagnosis of ACS is divided. Some disapprove its use because of the lack of
sensitivity for screening and the accuracy of the results. Others do approve
and recommend the use of POCT for troponin because it increases the ability to
diagnose and treat the disease. 1, 4, 5, 6, 7, 8

Purpose. The
aim of this study is to analyse the accuracy of POCT for the detection of troponin,
using blood samples of patients with acute coronary syndromes.