Cardiac Markers Overview

Creatine Kinase (CK)

• Normal range for males: 55–170 units/L
• Normal range for females: 30–135 units/L
• CK is found in cardiac muscle, skeletal muscle, and brain
• Elevated CK levels indicate injury to muscle cells
• CK levels peak 4–6 hours after muscle injury, remain elevated for 12–24 hours, and return to normal within 3–4 days

Creatine Kinase-MB (CK-MB)

• CK-MB is a specific type of CK found primarily in cardiac muscle
• CK-MB levels are usually less than 6% of total CK levels
• Elevated CK-MB levels indicate cardiac injury, such as acute myocardial infarction (AMI), cardiac ischemia, myocarditis, cardiac contusion, and/or defibrillation
• CK-MB levels peak 4–6 hours after cardiac injury, remain elevated for 18–24 hours, and return to normal within 3–4 days

Cardiac Troponin T

• Cardiac troponin T is a protein found specifically in cardiac muscle
• Elevated cardiac troponin T levels indicate AMI and/or unstable angina
• Levels rise 1–3 hours after cardiac injury, remain elevated for 12–16 hours, and return to normal within 10–14 days

Cardiac Troponin I

• Cardiac troponin I is a protein found exclusively in cardiac muscle
• Normal range: 0.1–0.5 ng/mL
• Elevated cardiac troponin I levels also indicate AMI and/or unstable angina
• Levels rise 1–3 hours after cardiac injury, remain elevated for 12–16 hours, and return to normal within 5–9 days

Creatine Kinase

• Creatine Kinase (CK) is an enzyme found in cardiac muscle, skeletal muscle, and the brain
• Elevated levels indicate muscle cell injury
• Normal ranges for males: 55–170 units/L
• Normal ranges for females: 30–135 units/L

Creatine Kinase-MB (CK-MB)

• CK-MB is a specific subtype of CK found primarily in cardiac muscle
• Elevated levels indicate cardiac injury, such as acute myocardial infarction (AMI), cardiac ischemia, myocarditis, cardiac contusion, and/or defibrillation
• Normal range: 0–6% of total CK

Cardiac Troponin T

• Cardiac Troponin T is a protein found in cardiac muscle
• Elevated levels indicate AMI and/or unstable angina
• Normal range: <0.1 ng/mL

Cardiac Troponin I

• Cardiac Troponin I is a protein found in cardiac muscle
• Elevated levels indicate AMI and/or unstable angina
• Normal range: 0.1–0.5 ng/mL

Time Course of Elevations

• CK and CK-MB:
  • Peak levels: 4-6 hours after injury
  • Return to normal levels: 12-24 hours after injury
  • May remain elevated for 3-4 days
• Cardiac Troponin T:
  • Peak levels: 1-3 hours after injury
  • Return to normal levels: 12-16 hours after injury
  • May remain elevated up to 10-14 days
• Cardiac Troponin I:
  • Peak levels: 1-3 hours after injury
  • Return to normal levels: 12-16 hours after injury
  • May remain elevated up to 5-9 days