Medical Terminology: Cardiac Enzymes and Markers Tests

1. What are Cardiac Enzymes and Markers Tests?
Cardiac muscle contains enzymes. In a myocardial infarction (MI) (heart attack), cardiac muscle is damaged, causing the release of cardiac enzymes into the bloodstream. When a patient is suspected of having a MI, the health care provider will order cardiac enzymes and cardiac marker tests to determine if cardiac muscle enzymes appear in the patient’s blood.
It can take 2. to 24. hours for cardiac muscle enzymes to reach a detectable level in blood. Therefore, health care providers typically use an electrocardiogram (EKG or ECG) to diagnose the acute phase of a MI. The cardiac enzymes and cardiac markers tests are used to confirm a previous acute MI.
There are several cardiac enzymes and cardiac marker tests commonly used by health care providers to confirm a myocardial infarction diagnosis.

2. Brain Natriuretic Peptide (BNP) Test
The brain natriuretic peptide (BNP) test is used to screen for heart failure and assess treatment for heart failure.

Understanding the Brain Natriuretic Peptide Test
The heart produces the hormone brain natriuretic peptide. A low level of BNP is normally found in blood. However, the BNP level increases when the heart works harder for long periods, such as in heart failure. The BNP test measures the level of BNP in the blood.
The health care provider may order the N-terminal probrain natriuretic peptide (NT-proBNP) test that measures the NT-proBNP hormone. This test provides diagnostic results that are similar to the BNP test.

3. Cardiac Enzyme Studies
Cardiac enzyme studies screen for an MI, cardiac muscle injury following bypass surgery, and unstable angina. It is also used to assess the results of percutaneous coronary intervention (PCI) or thrombolytic medication to restore blood flow through the coronary artery.

Understanding Cardiac Enzyme Studies
The cells of heart muscles and other tissues contain the enzyme creatinine phosphokinase (CPK) and the protein troponin (TnT, TnI). Creatinine phosphokinase and troponin enter the blood when heart muscle and other tissues are damaged. If levels of CPK and troponin are high, the health care provider orders an EKG to differentiate between heart muscle damage and other tissue damage. Troponin and CPK-MB are mostly found in cardiac muscle.
Blood samples are taken every 12. hours for 2. days following a suspected heart attack. It takes 6. hours for troponin levels to rise after a heart attack. The health care provider may order a myoglobin (MB) test along with the cardiac enzymes test to help diagnose a heart attack.

4. Homocysteine Test
The homocysteine test is used to assess risk for stroke and a heart attack.

Understanding the Homocysteine Test
Homocysteine is an amino acid found in blood, and the homocysteine test measures the level of homocysteine in blood. Homocysteine levels increase along with increased levels of cholesterol, which can lead to a risk of stroke, deep venous thrombosis, heart attack, and pulmonary embolism. The health care provider may order the homocysteine test for a patient who has a family history of heart disease but has not exhibited other risk factors. The health care provider may order a urine homocysteine test.

5. Renin Assay Test
The renin assay test is used to assess the underlying cause of hypertension.

Understanding the Renin Assay Test
Blood pressure is regulated by the renin angiotensin system (RAS). Low blood pressure causes the secretion of the renin enzyme by the kidneys, which increases angiotensin production. This increase constricts blood vessels, resulting in increased blood pressure. Angiotensin causes the adrenal cortex to replace aldosterone, causing the kidneys to retain water and sodium, which results in an increase in fluid volume and blood pressure. The renin assay test measures the level of renin in blood.
The health care provider may also order the aldosterone test. The renin stimulation test may be ordered if the renin level is low.

Basic Questions
Cardiac Enzymes and Markers Test

1. How long can it take before cardiac enzymes reach a detectable level in blood?
It can take 2. to 24. hours for cardiac muscle enzymes to reach a detectable level in blood.

2. What test is administered in the acute phase of a myocardial infarction (MI)?
Health care providers typically use an EKG to diagnose the acute phase of a MI.

3. What test might be ordered if the renin level is low?
The renin stimulation test.

4. What is the purpose of the brain natriuretic peptide (BNP) test?
The BNP test is used to screen for heart failure and assess the correct treatment.

5. What is BNP?
The heart produces the hormone brain natriuretic peptide.

6. Why is BNP measured?
The BNP level increases when the heart works harder for long periods, such as in heart failure.

7. What other hormone test might the health care provider order in addition to the BNP test?
The health care provider may order the N-terminal probrain natriuretic peptide (NT-proBNP) test, which measures the NT-proBNP hormone. This test provides diagnostic results similar to the BNP test.

8. What test might be administered following percutaneous coronary intervention (PCI) or thrombolytic medication to restore blood flow through the coronary artery?
Cardiac enzyme studies might be administered to restore blood flow through the coronary artery.

9. What test is administered following bypass surgery and why is it administered?
The cardiac enzyme studies test is administered to assess cardiac muscle injury following bypass surgery.

10. What is measured in the cardiac enzyme studies test?
Creatinine phosphokinase (CPK) and the protein troponin (TnT, TnI) are measured in the cardiac enzyme studies test.

11. Why might the health care provider order an EKG if CPK and troponin are high?
The health care provider might order an electrocardiogram to differentiate between heart muscle damage and other tissue damage.

12. Which enzyme and protein are mostly found in cardiac muscle?
Troponin and CPK-MB are mostly found in cardiac muscle.

13. How long does it take troponin levels to rise in blood following a myocardial infarction?
It takes 6. hours for troponin levels to rise after a heart attack.

14. How many times is the cardiac enzyme studies test administered following a suspected heart attack?
Blood samples are taken every 12. hours for 2. days following a suspected heart attack.

15. What is homocysteine?
Homocysteine is an amino acid found in blood.

16. What is the purpose of the homocysteine test?
The homocysteine test is used to assess risk for stroke and heart attack.

17. Why might a health care provider order the homocysteine test?
The health care provider may order the homocysteine test for a patient who has a family history of heart disease but has not exhibited other risk factors.

18. Why is homocysteine measured?
Homocysteine is measured because increased homocysteine levels along with increased levels of cholesterol can lead to a risk of stroke, deep venous thrombosis, heart attack, and pulmonary embolism.

19. Where is homocysteine measured?
Homocysteine is measured in blood and urine.

20. What is the purpose of the renin assay test?
The renin assay test is used to assess the underlying cause of hypertension.

21. How is blood pressure regulated?
Blood pressure is regulated by the renin angiotensin system (RAS).

22. What occurs during low blood pressure?
Low blood pressure causes the secretion of the renin enzyme by the kidneys, which increases angiotensin production and constricts blood vessels, resulting in increased blood pressure.

23. What is the function of angiotensin?
Angiotensin causes the adrenal cortex to replace aldosterone, causing the kidneys to retain water and sodium, and resulting in an increase in fluid volume and blood pressure.

24. What does the renin assay test measure?
The renin assay test measures the level of renin in the blood.

25. What would a high level of renin in blood indicate?
A high level of renin in the blood would indicate high blood pressure.