HealthFlex
×
  • Home
  • Immunology Book
  • Lab Tests
    • Hematology
    • Fluid analysis
    • CSF
    • Urine Analysis
    • Chemical pathology
    • Blood banking
    • Fungi
    • Immune system
    • Microbiology
    • Parasitology
    • Pathology
    • Tumor marker
    • Virology
    • Cytology
  • Lectures
    • Bacteriology
    • Liver
    • Lymph node
    • Mycology
    • Virology
  • Blog
    • Economics and technical
    • Fitness health
    • Mental health
    • Nutrition
    • Travel
    • Preventive health
    • Nature and photos
    • General topic
  • Medical Dictionary
  • About Us
  • Contact

Cardiac Marker:- Part 3 -Troponin-T, and Troponin-I

August 23, 2023Chemical pathologyLab Tests

Table of Contents

Toggle
  • Troponin-T, and Troponin-I
      • Sample for Troponin-T and Troponin-I
      • Indications for Troponin-T and Troponin-I
      • Definition of troponins:
      • Pathophysiology of Troponin-T and Troponin-I
      • Troponins and muscle injury:
      • Advantages of troponins:
        • Troponin and CK-MB difference:
      • Advantage of Troponin over CK-MB:
      • Normal Troponin-T, and Troponin-I
      • The pattern of Troponin-T in acute myocardial infarction:
      • Troponins interpretations:
      • Universal definition of acute myocardial infarction:
      • Positive or raised Troponin-I level seen in:
      • Positive or raised Troponin-T level was seen in:
      • Cardiac markers:
      • Questions and answers:

Troponin-T, and Troponin-I

Sample for Troponin-T and Troponin-I

  1. It is done on the EDTA blood.
  2. This test can also be done in the serum or plasma.
  3. A serial sample may be needed.
  4. The serum for troponin-T is stable for 24 hours at 2 to 8 °C.
    • Can store serum for three months at -20 °C.

Indications for Troponin-T and Troponin-I

  1. This test is advised to rule out myocardial infarction (MI) in a patient with chest pain.
  2. This is a specific indicator of cardiac damage or infarction.
  3. This helps diagnose MI at an early stage.
  4. This test is done for the early diagnosis of myocardial infarction.

Definition of troponins:

  1. Troponins are contractile proteins found within muscle fibers that help regulate contractions.
  2. Three troponins work as complex.
    1. Troponin-T = Tropomyosin-binding component.
    2. Troponin-I =  Inhibitory component.
    3. Troponin-C = Calcium-binding component.
  3. During muscle necrosis, Troponin-T and Troponin-I are released into blood circulation.
  4. Troponin-T and Troponin-I levels in the blood increase, indicating muscle necrosis.
  5. Troponins are not raised in angina.

Pathophysiology of Troponin-T and Troponin-I

  1. Troponins are proteins present in the skeletal and cardiac muscles.
  2. Troponins have three subunits complex:
    1. It will regulate the interaction of actin and myosin.
    2. These reactions of actin and myosin regulate cardiac contraction.
  3. These are regulatory proteins.
  4. Troponin is a complex of :
    1. Troponin-C is a Ca-binding component.
      1. It is not advised in AMI because this is not specific for myocardial muscles.
    2. Troponin-I is an inhibitory component.
    3. Troponin-T is a tropomyosin-binding component.
  5. Troponins are present in myofibrils around 94% to 97%.
    1. Troponin cytoplasmic fraction is 3% to 6%.
Troponin-T and Troponin-I interpretation

Troponin-T and Troponin-I interpretation

Troponins and muscle injury:

  1. There are kits for Troponin-I, but because of its three forms in circulation and their variation in concentration, different assays don’t produce reproducible results.
    1. Troponins remain in the blood circulation from 1 to 14 days after the onset of AMI.
  2. Troponin-T has no cross-reactivity with skeletal muscle, so this assay is 100 % specific for cardiac disease.
  3. Troponins help in the contraction of muscles, which is calcium-dependent, and there is an interaction between myosin and actin.
  4. There are two cardiac troponins:
    1. Troponin-T.
    2. Troponin-I.
    3. These are highly specific for cardiac muscle injury.
  5. Their role is just like CK-MB.
  6. Troponins are more specific than CK-MB.
    1. Troponins will be nearly normal or slightly raised in noncardiac muscle injuries.

Advantages of troponins:

  1. There is a quick release of troponins after the cardiac muscle injury (necrosis).
  2. These are present for a longer period of time after the heart attack.
  3. Troponins are measured by:
    1. Monoclonal antibody immunoassay.
    2. Enzyme-linked immunoassay.
    3. Monoclonal sandwich antibody qualitative technique.

Troponin and CK-MB difference:

Causative reason Troponin-T CK-MB
Skeletal muscle injury Normal Raised
Brain / Lung injury Normal Raised
Cardiac injury Raised Raised
Duration Raised for a longer time raised for a shorter time
Sensitivity More sensitive Less sensitive

Advantage of Troponin over CK-MB:

Characteristic feature Troponins CK-MB
Specificity
  1. More specifically for cardiac muscle injury.
  2. Normal in noncardiac muscle injury
  1. Increased skeletal muscle injury, brain, lung, and renal failure
Increased level
  1. Increased in 4 to 8 hours.
  2. It is  elevated longer than CK-MB
  1. It rises earlier than Troponin
  2. Disappears earlier than troponins.
Sensitivity 
  • More sensitive to cardiac muscle injury than CK-MB
  • Less sensitive to cardiac muscle injury
Importance 
  • More important for the evaluation of chest pain
  • Less important for the evaluation of chest pain

Normal Troponin-T, and Troponin-I

Source 1

  • Cardiac Troponin-T = < 0.2 ng/mL
  • Cardiac Troponin-I = < 0.03 mg/mL

Source 2

  • Troponin-T = 0 to 0.1 µg/L
  • Troponin-I = <3.1 µg/L

Source 3

  • Troponin I = <0.35 ng/mL
    • Or <0.35 µg/L
  • Troponin T = <0.2 ng/mL
    • Or <0.2 µg/L

The pattern of Troponin-T in acute myocardial infarction:

  1. Raised even in the first 3 hours.
  2. The peak level is 12 to 48 hours.
  3. Remain elevated for up to 10 to 14 days.
Troponins in AMI

Troponins in AMI

Troponins interpretations:

  1. Raised Troponin-T level establishes the diagnosis of AMI; even ECG or CK-MB is non-diagnostic (<50% of the cases).
  2. It indicates irreversible necrosis of the myocardial muscles.
  3. Serial troponin-T level normal rules out the possibility of myocardial necrosis (AMI).
  4. Troponins have replaced the CK-MB as the gold standard, replacing late diagnosis of AMI with the raised level of LDH.
  5. Troponin-T is as sensitive as CK-MB in the first 48 hours of the onset of AMI. It is >85% in concordance with CK-MB.
    1. Troponin-T sensitivity during 0 to 2 hours after the onset of chest pain = 33%
    2. Troponin-T sensitivity during 2 to 4 hours after the onset of chest pain = 50%.
    3. Troponin-T sensitivity during 4 to 8 hours after the onset of chest pain = 75%.
    4. Troponin-T sensitivity after 8 hours of the onset of chest pain          = 100%.
  6. Troponin-I is 13 times more abundant in the myocardium than CK-MB, providing.
  7. Troponin-I remained increased for <9 days, while Troponin-T was for 14 days.
    1. Troponins are increased in <50% of patients with acute pericarditis.
    2. A level of troponins <0.5 ng/mL indicates no myocardial damage.
    3. >2.0 ng/mL indicates some myocardial necrosis.

Universal definition of acute myocardial infarction:

  1. The Troponin value of at least one of these is >99% of the normal.
  2. The rapid rise in CK-MB and falls to normal.
  3. Evidence of the ischemia.
  4. Prominent Q-wave.
  5. Elevation of ST-segment.

Positive or raised Troponin-I level seen in:

  1. Myocardial injury during surgery.
  2. Small myocardial infarcts can be detected for up to 7 to 10 days.

Positive or raised Troponin-T level was seen in:

  1. Acute myocardial infarction.
  2. Pre-Surgical myocardial infarction.
  3. Unstable angina.
  4. Non-ischemic diseases of the heart:
    1. Acute trauma involving muscles.
    2. Rhabdomyolysis.
    3. Polymyositis.
    4. Dermatomyositis.
    5. Chronic renal failure.
    6. Myocarditis.
    7. Pericarditis.
    8. Heart failure.
    9. Pulmonary embolism.
    10. Sepsis.
    11. Shock.
    12. Renal insufficiency.

Cardiac markers:

Markers Detectable Peak level Return to normal
Troponin-T 4 to 8 hours 12 to 48 hours 7 to 10 days
Troponin- I 4 to 6 hours 12 hours 3 to 10 days
CK-MB 4 to 8 hours 12 to 24 hours 72 to 96 hours
LDH 2 to 5 days 10 days
AMI criteria for the diagnosis

AMI criteria for the diagnosis

Cardiac markers shown in the graph.

Cardiac markers

Questions and answers:

Question 1: What is the significance of the CK-MB for AMI?
Show answer
CK-MB has rapid rise and its fall. It rises earlier than troponin-T.
Question 2: What is the distribution of troponins in the cell cytoplasm?
Show answer
Troponin in the cytoplasm is 3% to 6%.

Possible References Used
Go Back to Chemical pathology

Add Comment Cancel



The reCAPTCHA verification period has expired. Please reload the page.

  • Lab Tests
    • Blood banking
    • Chemical pathology
    • CSF
    • Cytology
    • Fluid analysis
    • Fungi
    • Hematology
    • Immune system
    • Microbiology
    • Parasitology
    • Pathology
    • Tumor marker
    • Urine Analysis
    • Virology

About Us

Labpedia.net is non-profit health information resource. All informations are useful for doctors, lab technicians, nurses, and paramedical staff. All the tests include details about the sampling, normal values, precautions, pathophysiology, and interpretation.

[email protected]

Quick Links

  • Blog
  • About Us
  • Contact
  • Disclaimer

Our Team

Professor Dr. Riaz Ahmad Bhutta

Dr. Naheed Afroz Syed

Dr. Asad Ahmad, M.D.

Dr. Shehpar Khan, M.D.

Copyright © 2014 - 2025. All Rights Reserved.
Web development by Farhan Ahmad.