Unit 2: Laboratory Markers of Acute Cardiac Damage or Injury

Question 1

Laboratory Markers of Acute Cardiac Damage or Injury

Answer 1

• Creatinine Kinase (CK)
• Creatinine Kinase Myocardial Bands (CK-MB)
• Troponin
• Brain Natriuretic Peptide (BNP)
• Myoglobin

Question 2

Creatinine Kinase (CK)

Answer 2

• general marker for cellular injury

- released from cells in the brain, skeletal muscle, and cardiac tissue after muscle damage has occurred

Question 3

Creatinine Kinase Myocardial Bands (CK-MB)

Answer 3

0-3 mg/dL

• specific to cardiac tissue
• CK-MB releases from the cells when myocardial damage occurs
• increased levels can be seen at 3 hours after myocardial damage
• can remain elevated for up tp 36 hours until going back to normal

Question 4

Troponin

Answer 4

less than 0.4 mg/ml

• specific marker of cardiac muscle damage
• preferred method for diagnosing cardiac injury
• protein released from damaged tissue
• can elevate within 4 hours of injury
• stay elevated for up to 10 days (reason why it is a valuable marker for diagnosing injury in recent past)

Question 5

Brain Natriuretic Peptide (BNP)

Answer 5

less than 100 pg/ml

• is released from overstretched ventricular tissue; venous dilation, which decreases preload, arterial dilation which decreases afterload, and diuresis
• elevations (greater than 100) are indicative of HF

Question 6

Myoglobin

Answer 6

0-85 mg/ml

• protein released and elevated in muscle damage
• not specific for cardiac tissue
• can be sued in conjunction with other values

Question 7

Nursing Implications r/t Obtaining CK, CK-MB, and Troponin

Answer 7

timing of blood draws

-for acute injury, lab tests obtained at baseline and then at regular intervals (3 to 4 hours) for 12 hours