Troponin T, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Exclusion diagnosis of acute myocardial infarction
Monitoring acute coronary syndromes and estimating prognosis
Possible utility in monitoring patients with nonischemic causes of cardiac injury
Troponin T is the cardiac marker of choice for the Mayo Health System for the evaluation of patients with possible cardiovascular injury
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Troponin T, S
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Preferred: Serum gel
Acceptable: Red top or rapid serum tube (RST)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild reject; Gross reject
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum||Frozen (preferred)||365 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Troponin T is a myofibrillar protein found in striated musculature. There are 2 types of myofilament, a thick filament containing myosin and a thin filament consisting of 3 different proteins: actin, tropomyosin, and troponin. Troponin is itself a complex of 3 protein subunits: troponin T, troponin I, and troponin C. Troponin T binds the troponin complex to tropomyosin. Troponin I inhibits actomyosin ATPase in relation to the calcium concentration. Troponin C, with its 4 binding sites for calcium, mediates calcium dependency.
In the cytosol, troponin T is found in both free and protein-bound forms. The unbound (free) pool of troponin T is the source of the troponin T released in the early stages of myocardial damage. Bound troponin T is released from the structural elements at a later stage, corresponding with the degradation of myofibrils that occurs in irreversible myocardial damage. The most common cause of cardiac injury is myocardial ischemia, ie, acute myocardial infarction. Troponin T becomes elevated 2 to 4 hours after the onset of myocardial necrosis, and can remain elevated for up to 14 days.
Elevations in troponin T are also seen in patients with unstable angina. The finding of unstable angina and an elevated troponin T are known to have adverse short- and long-term prognoses, as well as a unique beneficial response to an invasive interventional strategy and treatment with the newer antiplatelet agents and low-molecular-weight heparin.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Values > or =0.01 ng/mL have been shown to have prognostic value.
The upper limit for normal individuals is <0.01 ng/mL (undetectable by this method).
For patients who present with acute coronary syndromes, troponin T values > or =0.01 ng/mL that are rising make the diagnosis of cardiac injury. Decreasing values are indicative of recent cardiac injury.
Troponin T values > or =0.01 ng/mL are a prognostic sign in patients with ischemic heart disease and most other situations. Clinical judgment is necessary to distinguish patients who have ischemic heart disease from those who do not. However, all patients with > or =0.01 ng/mL troponin T are at increased risk for cardiac events relative to patients with undetectable troponin T.
Patients with low level (<0.20 ng/mL) elevations of troponin T and diagnostic uncertainty for acute coronary syndrome should be evaluated by repeat measurements at 3 and 6 hours including a delta between these time points to determine whether this is an acute or more chronic elevation. However, all patients with > or =0.01 ng/mL troponin T are at increased risk for cardiac events relative to patients with undetectable troponin T.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
As with all markers of cardiac injury, elevations of troponin T do not in and of themselves indicate the presence of an ischemic mechanism. Many other disease states are associated with elevations of troponin T via mechanisms different from those that cause injury in patients with acute coronary syndromes. These include trauma (eg, contusion, ablation, or pacing), congestive heart failure, hypertension, hypotension (often with arrhythmias), pulmonary embolism, renal failure, and myocarditis.
Various cutoffs have been proposed to identify patients with acute coronary syndromes and those at risk for future cardiac events. The cutoff used in earlier clinical studies (receiver operator curve cutoff) was around 0.10 ng/mL troponin T. This cutoff misses many patients at risk for short- or long-term adverse outcomes. The cutoff previously used at Mayo Clinic, 0.03 ng/mL, was based on the analytical performance of existing methodology for troponin T, and was chosen to approximate the level that could be measured with <10% imprecision. More recent recommendations suggest that a level of troponin T that exceeds the 99th percentile of values found in a healthy population optimizes identification of patients at risk of cardiac events. Levels seen in the normal population are undetectable (<0.01 ng/mL) by the current troponin T assay.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Jaffe AS: 2001-A biomarker odyssey. Clin Chim Acta 1999;284:197-211
Method Description Describes how the test is performed and provides a method-specific reference
The E Modular troponin T method employs 2 monoclonal antibodies specifically directed against human cardiac troponin T. A biotinylated monoclonal antibody and a second monoclonal antibody labeled with a ruthenium complex react with troponin T to form a sandwich complex. After the addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Application of a voltage to the electrode then induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Troponin T STAT, Roche Diagnostics Corporation, Indianapolis IN)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|TPNT||Troponin T, S||6598-7|