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22935 Troponin I

Troponin I
Test Code: TNI
Useful For
Exclusion diagnosis of acute myocardial infarction.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Plasma or Serum​ Lithium-heparin Plasma Separator Tube (PST) Serum Separator Tube (SST), Red Top Tube (RTT)​ 1.0 mL​ 0.3 mL​ 0.3 mL​
Collection Processing Instructions
Separate plasma or serum from the blood within 60 minutes of venipuncture. Specimen must be free of particulate matter including fibrin which can interfere with the assay.
For plasma samples only:
- Sites with centrifuges capable of reaching a speed of 4,400g can centrifuge the collection tube for 3 minutes.
- Sites with standard centrifugation must centrifuge the collection tube for 10 minutes at 1900g.
 
High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay. It is recommended that patients refrain from consuming any multivitamin or supplement containing biotin for at least 72 hours prior to collection of a blood sample.
Specimen Stability Information
Specimen Type Temperature Time
Serum or Plasma​ ​ ​ ​ Ambient​ 8 hours
Refrigerate <72 hours
​Frozen at -20 deg Celsius ​1 month
​Frozen at -70 deg Celsius > 1 month

​ ​Preferably outreach specimens should be frozen.  
Avoid freeze and thaw of samples.  One freeze and thaw is acceptable. ​

Rejection Criteria
Serum specimens exposed to repeated freeze/thaw cycles
Interference

High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay.

Heterophile Antibodies and Rheumatoid factor can react with reagent immunoglobulins.  Human anti-mouse antibodies may cause falsely low or high results.  Troponin autoantibodies may interfere. 

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Diagnostic Treatment Center​ ​Monday through Sunday​ ​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Flambeau Hospital ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
Lakeview Medical Center​ ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 1 hour​ Chemiluminescent Immunoassay/Siemens Centaur
​Minocqua ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Wausau ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Wisconsin Rapids ​Monday through Sunday ​Less than 2 hours ​Enzyme Immunoassay/Siemens Dimension
Reference Range Information
Performing LocationReference Range
Marshfield
Female: <= 37 ng/L
Male: <= 57 ng/L
​All Performing Sites using Siemens Dimension
​<= 45 ng/L
The 99th percentile Upper Reference Limit (URL) for troponin I in a normal reference population is used. All assays show less than 10% imprecision (<10% CV) at 99th percentile upper reference limit value. Reference values were adopted and validated from the manufacturer's normal population studies.
Interpretation

For high sensitivity TNI assay used at MMC Marshfield lab:

Serial measurements may be necessary to confirm or exclude the diagnosis of acute coronary syndrome. Repeat testing in 2 hours if clinically indicated.

-If zero hour TNI is <8 ng/L  AND  delta at two hours is < 7 ng/L, then rule out Acute MI.

-If zero hour TNI is >=120 ng/L  OR  delta at two hours is >=20 ng/L, then rule in Acute MI.

-If results do not fall into above, then observe. Getting additional draws (e.g. at 4 hours) may be helpful.

For all other sites reporting TNI:

The 99th percentile URL for troponin I in a normal reference population is approximately 45 ng/L.

Values >45 ng/L are consistent with myocardial injury.

Serial measurements may be necessary to confirm or exclude the diagnosis of acute coronary syndrome.

Repeat testing in 3 to 6 hours if clinically indicated.

Cardiac Troponin I (cTnI) is very specific to myocardium and not expressed during any developmental stage in skeletal muscle. Increased levels of cTnI are detected with myocardial injury. Detection of rise and/or fall of cTnI are essential to establish the diagnosis of acute myocardial infarction (MI). An increased cTnI concentration is defined as a value exceeding the upper reference limit of the 99th percentile of a normal reference population and is designated as the decision limit for the diagnosis of acute MI (Third Universal definition of Myocardial infarction, ESC/ACCF/AHA/WHF Expert consensus document. Circulation 2012; 126: 2020). Demonstration of rising and/or falling pattern is required to distinguish acute from elevations of cTnI levels that are associated with chronic heart diseases.

A positive cTnI result therefore, is not always indicative of ischemia. Other conditions resulting in myocardial cell damage can contribute to elevated cTnI include, but are not limited to:

Elevated Tnl Values in Patients Without AMI

Cardiac conditions

  Angina/Unstable Angina

  Atrial fibrillation

   Cardiac surgery

  Cardiomyopathy

  Congestive heart failure

  Coronary artery disease

   Heart failure

   Hypertensive urgency

   Myocarditis

   Pericarditis

  Pulmonary emoblism

   Recent cardiac intervention

   Severe valvular heart disease

   Tachycardia

 

Non-cardiac conditions

   Chronic lung disease

   Cardiac contusion related to a traumatic injury

   Renal failure

   Pneumonia

   Pulmonary embolism

For assessing acute MI, blood samples should be drawn at the time of admission and repeated at 3 to 6 hours intervals. On certain occasions additional samples between 12 and 24 hours may be required if earlier measurements are not elevated and clinical suspicion is high for MI.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
84484 ​
Ordering Applications
Ordering Application Description
​Centricity

​a. Troponin I (TNI)

b. Troponin I

​Cerner ​Troponin-I
​COM Troponin I
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Plasma or Serum​ Lithium-heparin Plasma Separator Tube (PST) Serum Separator Tube (SST), Red Top Tube (RTT)​ 1.0 mL​ 0.3 mL​ 0.3 mL​
Collection Processing
Separate plasma or serum from the blood within 60 minutes of venipuncture. Specimen must be free of particulate matter including fibrin which can interfere with the assay.
For plasma samples only:
- Sites with centrifuges capable of reaching a speed of 4,400g can centrifuge the collection tube for 3 minutes.
- Sites with standard centrifugation must centrifuge the collection tube for 10 minutes at 1900g.
 
High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay. It is recommended that patients refrain from consuming any multivitamin or supplement containing biotin for at least 72 hours prior to collection of a blood sample.
Specimen Stability Information
Specimen Type Temperature Time
Serum or Plasma​ ​ ​ ​ Ambient​ 8 hours
Refrigerate <72 hours
​Frozen at -20 deg Celsius ​1 month
​Frozen at -70 deg Celsius > 1 month

​ ​Preferably outreach specimens should be frozen.  
Avoid freeze and thaw of samples.  One freeze and thaw is acceptable. ​

Rejection Criteria
Serum specimens exposed to repeated freeze/thaw cycles
Interference

High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay.

Heterophile Antibodies and Rheumatoid factor can react with reagent immunoglobulins.  Human anti-mouse antibodies may cause falsely low or high results.  Troponin autoantibodies may interfere. 

Useful For
Exclusion diagnosis of acute myocardial infarction.
Reference Range Information
Performing LocationReference Range
Marshfield
Female: <= 37 ng/L
Male: <= 57 ng/L
​All Performing Sites using Siemens Dimension
​<= 45 ng/L
The 99th percentile Upper Reference Limit (URL) for troponin I in a normal reference population is used. All assays show less than 10% imprecision (<10% CV) at 99th percentile upper reference limit value. Reference values were adopted and validated from the manufacturer's normal population studies.
Interpretation

For high sensitivity TNI assay used at MMC Marshfield lab:

Serial measurements may be necessary to confirm or exclude the diagnosis of acute coronary syndrome. Repeat testing in 2 hours if clinically indicated.

-If zero hour TNI is <8 ng/L  AND  delta at two hours is < 7 ng/L, then rule out Acute MI.

-If zero hour TNI is >=120 ng/L  OR  delta at two hours is >=20 ng/L, then rule in Acute MI.

-If results do not fall into above, then observe. Getting additional draws (e.g. at 4 hours) may be helpful.

For all other sites reporting TNI:

The 99th percentile URL for troponin I in a normal reference population is approximately 45 ng/L.

Values >45 ng/L are consistent with myocardial injury.

Serial measurements may be necessary to confirm or exclude the diagnosis of acute coronary syndrome.

Repeat testing in 3 to 6 hours if clinically indicated.

Cardiac Troponin I (cTnI) is very specific to myocardium and not expressed during any developmental stage in skeletal muscle. Increased levels of cTnI are detected with myocardial injury. Detection of rise and/or fall of cTnI are essential to establish the diagnosis of acute myocardial infarction (MI). An increased cTnI concentration is defined as a value exceeding the upper reference limit of the 99th percentile of a normal reference population and is designated as the decision limit for the diagnosis of acute MI (Third Universal definition of Myocardial infarction, ESC/ACCF/AHA/WHF Expert consensus document. Circulation 2012; 126: 2020). Demonstration of rising and/or falling pattern is required to distinguish acute from elevations of cTnI levels that are associated with chronic heart diseases.

A positive cTnI result therefore, is not always indicative of ischemia. Other conditions resulting in myocardial cell damage can contribute to elevated cTnI include, but are not limited to:

Elevated Tnl Values in Patients Without AMI

Cardiac conditions

  Angina/Unstable Angina

  Atrial fibrillation

   Cardiac surgery

  Cardiomyopathy

  Congestive heart failure

  Coronary artery disease

   Heart failure

   Hypertensive urgency

   Myocarditis

   Pericarditis

  Pulmonary emoblism

   Recent cardiac intervention

   Severe valvular heart disease

   Tachycardia

 

Non-cardiac conditions

   Chronic lung disease

   Cardiac contusion related to a traumatic injury

   Renal failure

   Pneumonia

   Pulmonary embolism

For assessing acute MI, blood samples should be drawn at the time of admission and repeated at 3 to 6 hours intervals. On certain occasions additional samples between 12 and 24 hours may be required if earlier measurements are not elevated and clinical suspicion is high for MI.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Diagnostic Treatment Center​ ​Monday through Sunday​ ​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Flambeau Hospital ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
Lakeview Medical Center​ ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 1 hour​ Chemiluminescent Immunoassay/Siemens Centaur
​Minocqua ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Wausau ​Monday through Sunday​ ​​Less than 2 hour​s ​Enzyme Immunoassay/Siemens Dimension
​Wisconsin Rapids ​Monday through Sunday ​Less than 2 hours ​Enzyme Immunoassay/Siemens Dimension
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
84484 ​
For most current information refer to the Marshfield Laboratory online reference manual.