Troponin T
Label Mnemonic: TROPT
Epic Lab Code: LAB139
Downtime Form: A-1a General Laboratory Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL; plasma separator tube top or TWO Microtainer® devices.
Rejection Criteria:
Red top tube is not acceptable.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
Is less than or equal to 0.10 ng/mL

Clinically significant value >10 ng/mL (outpatient only, excluding ED (Emergency Department), implemented 3/21/17).
Comments:
Elevated troponin T levels are generally indicative of myocardial injury, but elevations are not synonymous with an ischemic mechanism of injury. If the clinical circumstance suggests that an ischemic mechanism is unlikely, other causes of cardiac injury should be considered. Less commonly, troponin T elevations have been seen in patients with rhabdomyolysis, dermatomyositis and polymyositis.

Myocardial cell injury leading to elevated troponin T concentrations in the blood can occur with congestive heart failure, cardiomyopathy, myocarditis, heart contusion, renal failure, lung embolism, stroke, left ventricular dysfunction in septic shock, and interventional therapy like cardiac surgery, non-cardiac surgery, and drug-induced cardiotoxicity.

References:
1. Mair J, Dienstl F, Puschendorf B. Cardiac Troponin T in the Diagnosis of Myocardial Injury. Critical Reviews in Clin Lab Sci 1992;29(1):31-57.

2. Jaffe AS, Ravkilde J, Roberts R, et al. It's time for a change to a troponin standard. Circulation 2000;102:1216-1220.

3. Apple FS, Wu AHB. Myocardial infarction redefined: Role of cardiac troponin Testing. Clin Chem 2001;47:377-379.

4. Kobayashii S, Tanaka M, Tamura N, et al. Serum cardiac troponin T in polymyositis/dermatomyositis. Lancet 1992;340(8821):726.

5. Fisher C, Agrawal S, Wong WM, Fahie-Wilson M, Dasgupta B. Clinical observations on the significance of raised cardiac troponin-T in patients with myositis of varying etiologies seen in rheumatology practice. Clin Rheumatol. 2010 Oct;29(10):1107-11.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).
Test Limitations:
The assay is unaffected by icterus (bilirubin is less than 27 mg/dL), hemolysis (Hb is less than 300 mg/dL), lipemia (Intralipid is less than 1500 mg/dL) and biotin is less than 50 ng/mL (criterion: recovery within plus or minus 10% of initial value). In patients receiving therapy with high biotin doses (i.e. is greater than 5 mg/day) no sample should be taken until at least 8 hours after the last biotin administration. No interference was observed from rheumatoid factor up to 2000 IU/mL. There is no high-dose hook effect for troponin T concentrations up to 400 ng/mL. In vitro tests were performed on 50 commonly used pharmaceuticals. No interference with the assay was found. Plasma samples collected using tubes containing oxalate/fluoride, revealed sample-dependent low troponin T values when compared to results obtained on serum samples. Therefore, do not use oxalate/fluoride plasma samples for the assay. As with all tests containing monoclonal mouse antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies or have received them for diagnostic purposes. In rare cases, interference due to extremely high titers of antibodies to streptavidin can occur. Troponin T reagent contains additives which minimize these effects. Extremely high titers of antibodies to ruthenium can occur in isolated cases and cause interference. For diagnostic purposes, the Troponin T findings should always be assessed in conjunction with the patient's medical history, clinical examination and other findings.
Methodology:
Electrochemiluminescence Immunoassay
CPT Code:
84484
 
See Additional Information:
Chemistry Critical Lab Values