Cardiac markers: a clear cause for point-of-care testing

Abstract

Point-of-care testing (POCT) in patients with ischemic heart disease is driven by the time-critical need for fast, specific, and accurate results to initiate therapy instantly. According to current guidelines, the results of the cardiac marker testing should be available to the physician within 30 min ("vein-to-brain" time) to initiate therapy within 60-90 min ("door-to-needle" time) after the patient has arrived at the emergency room or intensive care unit. This article reviews the current efforts to meet this goal (1) by implementing POCT of established biochemical markers such as cardiac troponins, creatine kinase MB, and myoglobin, in accelerated diagnosis and management workflow schemes, (2) by improving current POCT methods to obtain more accurate, more specific, and even faster tests through the integration of optical and electrochemical sensor technology, and (3) by identifying new markers for the very early and sensitive detection of myocardial ischemia and necrosis. Furthermore, the specific requirements for cardiac POCT in regard to analytical performance, comparability, and diagnostic sensitivity/specificity are discussed. For the future, the integration of new immunooptical and electrochemical chip technology might speed up diagnosis even further. However, every new development will have to meet the stringent method validation criteria set for corresponding central laboratory testing.

Point-of-care diagnostics for niche applications

“…To expedite diagnosis, many EDs have successfully introduced POC devices to test for cTnI (Bingisser et al, 2012, Friess and Stark, 2009). However, while there are many different devices currently on the market that are capable of making this measurement (Yang and Min Zhou, 2006), there are currently no CLIA-waived tests for troponin (www.accessdata.fda.gov, 2015).…”

An Electrochemical Biosensor Based on a Myoglobin-specific Binding Peptide for Early Diagnosis of Acute Myocardial Infarction

“…Due to its small size of 17.8 kDa, myoglobin is quickly released into circulation within 1 -3 h after symptom onset, and serves as a valuable screening molecule with high sensitivity and predictivity for AMI detection. [3][4][5] Optical biosensors, including a sandwich immunoassay with secondary labeled antibodies, enzyme-linked immunosorbent assay (ELISA), fluorescence, and surface plasma resonance (SPR), have been used for the detection of cardiac markers, such as troponin I, myoglobin, c-reactive protein (CRP), and myeloperoxidase (MPO). [6][7][8][9][10] Driven by a clinical need for pointof-care diagnostics, next-generation biosensors with improved sensitivity and specificity have attracted increasing attention in recent years, leading to the development of peptide-based sensing approaches.…”

Elevated Soluble fms-Like Tyrosine Kinase-1 Levels in Acute Coronary Occlusion

“…24 -29 Recently, ultrasensitive troponin assays have demonstrated improved sensitivity for detecting an AMI. 6 However, patients presenting with myocardial injury from any cause may yield a positive ultrasensitive troponin test result, compromising the value of these tests for identifying patients presenting specifically with an ACO. Furthermore, despite advancements in troponin assay development, myocyte necrosis is still required for these assays to be useful.…”

“…4 The difficulty of timely identification of ACO is increased further because currently used biomarkers for the diagnosis of AMI, 5 such as the MB isoform of creatine (CK) kinase (CK-MB), myoglobin, and standard or ultrasensitive troponin require cardiomyocyte damage and may not be specific to coronary occlusion. 6,7 Therefore, relying on the ECG or biomarkers of myocyte necrosis to distinguish ACO from noncardiac causes of chest pain may be accompanied by both false-positive and negative results.…”