Myocardial infarction (MI) is the leading cause of death in the developed world. Biomarkers have an essential role in diagnosis, risk stratification, guiding management and clinical decision making in the setting of patients presenting with signs and symptoms of MI. Cardiac troponin (cTn) rose to prominence during the 1990s and has evolved to be the cornerstone for diagnosis of MI. The current criteria for MI diagnosis include a rise and/or fall in cTn with at least one value above the 99th percentile of the upper reference limit. Along with cTn, the natriuretic peptides B-type natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) have an important role in determining prognosis and guiding management. As assays for cTn have been evolved that are capable of reliably detecting smaller and smaller quantities in the blood, a dilemma has emerged as to how to use this new information. Several studies have attempted to answer this question and have shown that these lower concentrations of cTn have important prognostic significance and, more importantly, that intervention in these patients leads to improved clinical outcomes. New algorithms incorporating BNP, NT-proBNP, and more sensitive cTn assays hold promise for more rapid diagnosis or rule-out of MI, allowing for appropriate management steps to be initiated and more efficient and effective utilization of healthcare resources.
Biological Markers/*blood ; Humans ; Myocardial Infarction/*diagnosis/metabolism ; Natriuretic Peptide, Brain/blood ; Peptide Fragments/blood ; Prognosis ; Troponin/blood

Results between different clinical laboratory measurement procedures (CLMP) should be equivalent, within clinically meaningful limits, to enable optimal use of clinical guidelines for disease diagnosis and patient management. When laboratory test results are neither standardized nor harmonized, a different numeric result may be obtained for the same clinical sample. Unfortunately, some guidelines are based on test results from a specific laboratory measurement procedure without consideration of the possibility or likelihood of differences between various procedures. When this happens, aggregation of data from different clinical research investigations and development of appropriate clinical practice guidelines will be flawed. A lack of recognition that results are neither standardized nor harmonized may lead to erroneous clinical, financial, regulatory, or technical decisions. Standardization of CLMPs has been accomplished for several measurands for which primary (pure substance) reference materials exist and/or reference measurement procedures (RMPs) have been developed. However, the harmonization of clinical laboratory procedures for measurands that do not have RMPs has been problematic owing to inadequate definition of the measurand, inadequate analytical specificity for the measurand, inadequate attention to the commutability of reference materials, and lack of a systematic approach for harmonization. To address these problems, an infrastructure must be developed to enable a systematic approach for identification and prioritization of measurands to be harmonized on the basis of clinical importance and technical feasibility, and for management of the technical implementation of a harmonization process for a specific measurand.
Humans ; Sensitivity and Specificity

Objective: To determine the utility of a highly sensitive troponin assay when utilized in the emergency department. Methods The FAST-TRAC study prospectively enrolled >1,500 emergency department patients with suspected acute coronary syndrome within 6 hours of symptom onset and 2 hours of emergency department presentation. It has several unique features that are not found in the majority of studies evaluating troponin. These include a very early presenting population in whom prospective data collection of risk score parameters and the physician’s clinical impression of the probability of acute coronary syndrome before any troponin data were available. Furthermore, two gold standard diagnostic definitions were determined by a pair of cardiologists reviewing two separate data sets; one that included all local troponin testing results and a second that excluded troponin testing so that diagnosis was based solely on clinical grounds. By this method, a statistically valid head-to-head comparison of contemporary and high sensitivity troponin testing is obtainable. Finally, because of a significant delay in sample processing, a unique ability to define the molecular stability of various troponin assays is possible.Trial registration ClinicalTrials.gov Identifier NCT00880802