ReviewPresent issues in the determination of troponins and other markers of cardiac damage
Section snippets
Background
T he field of biochemical markers of cardiac damage is in a dynamic state, with new applications continually appearing and new assays and markers being developed. The availability of innovative procedures to detect myoglobin, cardiac troponin I (cTnI) and troponin T (cTnT), and creatine kinase (CK)-MB mass concentration instead of isoenzyme activity represents a major opportunity to improve significantly clinical assessment of the acute coronary syndrome 1, 2.
Myoglobin was the first
The ongoing issues
These significant and sudden advancements in the development of new biochemical assays for myocardial damage have led to some analytical and interpretative problems (20). There are problems in test standardization, imprecision, and of preanalytical variability; problems also arise with turnaround time and evaluation of point-of-care testing (POCT) devices as a possible alternative in particular situations. We lack accurate economic analyses that consider costs in relation to expected benefits,
Cardiac POCT
Use of POCT devices is another means to deliver emergency cardiac marker results. Advocates of this approach point out the speed and convenience of such testing. POCT devices are now available for myoglobin, CK-MB mass, cTnI, and cTnT (54). These make use of anticoagulated whole blood and provide results within 15 min. Elimination of the need to deliver samples to the central laboratory and centrifugation enables shorter processing time. However, unit costs for POCT are higher than for tests
Improving sensitivity of cardiac troponin assays
An interesting area of further analytical development that may have some clinical utility would be to improve the level of analytical sensitivity of the troponin assays in an attempt to investigate some of the situations in which subtle degrees of myocardial injury may be cumulative, and in which early detection may be helpful. This effort was recently furthered by two investigations by Missov and a group of Sanofi scientists 65, 66 using a new generation, highly sensitive immunoassay for cTnI
References (67)
- et al.
Diagnostic strategies using myoglobin measurement in myocardial infarction
Clin Chim Acta
(1998) Diagnostic application of CK-MB mass measurement
Clin Chim Acta
(1998)- et al.
Three rapid immunoassays for the determination of creatine kinase MBan analytical, clinical, and interpretive evaluation
Am Heart J
(1991) - et al.
Early detection of acute myocardial infarction by measurement of mass concentration of creatine kinase-MB
Am J Cardiol
(1991) Tissue specificity of cardiac troponin I, cardiac troponin T and creatine kinase-MB
Clin Chim Acta
(1999)An overview and ranking of biochemical markers of cardiac disease. Strengths and limitations
Clin Lab Med
(1997)- et al.
The lack of standardization of cardiac troponin I assay systems
Clin Chim Acta
(1999) - et al.
High percentage of false positive cardiac troponin I results in patients with rheumatoid factor
Clin Biochem
(1999) Analytical and clinical evaluation of new diagnostic tests for myocardial damage
Clin Chim Acta
(1998)- et al.
Cardiac markerspoint of care testing
Clin Chim Acta
(1999)
Troponin, where do we go from here?
Clin Lab Med
Biochemical assessment of myocardial damage with new diagnostic tools
Cardiologia
Biochemical markers of cardiac damagefrom traditional enzymes to cardiac-specific proteins
Scand J Clin Lab Invest
Myoglobin
The sensitivity of cardiac markersan evidence-based approach
Clin Chem Lab Med
Evidence based approach to practice guides and decision thresholds for cardiac markers
Scand J Clin Lab Invest
Acute myocardial infarction and coronary reperfusion. Serum cardiac markers for the 1990s
Am J Clin Pathol
Equivalent early sensitivities of myoglobin, creatine kinase MB mass, creatine kinase isoform ratios, and troponin I and T for acute myocardial infarction
Clin Chem
Cardiac troponin T as a marker of myocardial injury
Cardiac troponin I
Serum cardiac troponin I and T in early posttraumatic rhabdomyolysis
Clin Chem
Comparison of cardiac troponin I and lactate dehydrogenase isoenzymes for the late diagnosis of myocardial injury
Am J Clin Pathol
Cardiac-specific troponins in acute coronary syndromes
Troponin Ta diagnostic marker for myocardial infarction and minor cardiac cell damage
Eur Heart J
Troponin Istructure, physiology and its role in risk stratification of angina patients
IFCC Committee on standardization of markers of cardiac damagepremises and project presentation
Clin Chem Lab Med
Characterization of cardiac troponin subunit release into serum after acute myocardial infarction and comparison of assays for troponin T and I
Clin Chem
Comparison of immunoreactivity of five human cardiac troponin I assays toward free and complexed forms of the antigenimplications for assay discordance
Clin Chem
Troponin I is released in bloodstream of patients with acute myocardial infarction not in free form but as complex
Clin Chem
Determination of cardiac troponin I forms in the blood of patients with acute myocardial infarction and patients receiving crystalloid or cold blood cardioplegia
Clin Chem
Characterization and measurement of troponin I, troponin T and troponin complexes in blood from AMI patients
Clin Chem
Monoclonal antibodies affected by cardiac troponin I phosphorylationis part of troponin in the blood of myocardial infarction patients phosphorylated?
Clin Chem Lab Med
Stability of human cardiac troponin I (cTnI) in homogenates of necrotic tissue of human cardiac muscle
Clin Chem
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2004, British Journal of AnaesthesiaCitation Excerpt :It is not surprising that absolute values obtained using different manufacturers’ assays may not be comparable, and may differ numerically by up to 20-fold. There is also evidence that some cTnI assays were inadequately appraised before their introduction into routine clinical use.102 The situation for cTnT assays is much clearer than that for cTnI.
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