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Lab Test: Creatine Kinase, CK Level

    Lab Test
    • Creatine Kinase (CK)
    • Measurement of serum CK levels
    Reference Range
    • Adult/elderly:  (Values are higher after exercise):
      • Male:  55-170 units/L
      • Female:  30-135 units/L
    • Newborn:  68-580 units/L
    • Isoenzymes:
      • CK-MM:  100%
      • CK-MB:  0%
      • CK-BB:  0%
    Indications & Uses
    • To support the diagnosis of myocardial muscle injury (infarction)
    • To indicate neurologic disease
    • To indicate skeletal muscle diseases
    Clinical Application
    • CK is found predominantly in the heart muscle, skeletal muscle, and brain and are elevated when these muscle or nerve cells are injured.  They can rise within 6 hours after damage and if damage does not continue, the levels peak at 18 hours after injury and return to normal in 2 to 3 days. 
    • To test specifically for myocardial muscle injury electrophoresis is performed to detect the three CK isoenzymes:  CK-BB (CK1), CK-MB (CK2), and CK-MM (CK3).  The CK-MB isoenzyme portion appears to be specific for myocardial cells.  CK-MB levels rise 3 to 6 hours after infarction occurs, peak at 12 to 24 hours (if there is no further myocardial damage), and return to normal 12 to 48 hours after infarction.  One can expect to see a rise in CK-MB in patients with shock, malignant hyperthermia, myopathies, or myocarditis.  Mild elevation of CK-MB (below the threshold of positive) can occur in patients with unstable angina and will signify a increased risk for an occlusive event. 
    • Increased levels of total CK may indicate:
      • Diseases or injury affecting the heart muscle, skeletal muscle, and brain
    • Increased levels of CK-BB isoenzyme may indicate:
      • Diseases that affect the CNS (e.g., brain injury, brain cancer, cerebrovascular accident [stroke], subarachnoid hemorrhage, seizures, shock, Reye syndrome), electroconvulsive therapy, adenocarcinoma (especially breast and lung), or pulmonary infarction
    • Increased levels of CK-MB isoenzyme may indicate:
      • AMI, cardiac aneurysm surgery, cardiac defibrillation, myocarditis, ventricular arrhythmias, or cardiac ischemia
    • Increased levels of CK-MM isoenzyme may indicate:
      • Rhabdomyolysis, muscular dystrophy, myositis, recent surgery, electromyography, IM injections, trauma, crush injuries, delirium tremens, malignant hyperthermia, recent convulsions, ECT, shock, hypokalemia, or hypothyroidism.
    Related Tests
    • Aspartate aminotransferase (AST) - elevated levels of this enzyme may indicate cardiac injury.
    • Lactic dehydrogenase (LDH) - used to support the diagnosis of injury or disease involving the heart, liver, red blood cells, kidneys, skeletal muscle, brain, and lungs. 
    • Alanine aminotransferase (ALT) - used similarly to AST and exists predominantly in the liver.
    • Leucine aminopeptidase (LAP) - specific to the hepatobiliary system.  Diseases affecting that system will cause elevation of this enzyme. 
    • Gamma-glutamyl transpeptidase (GGTP) - exists predominantly in the liver.
    • Alkaline phosphatase - enzyme that exists predominantly in the liver.
    • 5'-nucleotidase - enzyme existing predominantly in the liver.
    • Troponins - biochemical marker used to assist in the evaluation of patients with chest pain.
    Drug-Lab Interactions
    • Intramuscular (IM) injections can cause elevated CK levels.
    • Strenuous exercise and recent surgery may cause increased levels.
    • Early pregnancy may produce decreased levels.
    • Muscle mass is directly related to a patient's normal CK level. 
    • Drugs that may cause increased levels include:  alcohol, amphotericin B, ampicillin, some anesthetics, anticoagulants, aspirin, captopril, clofibrate, colchicine, dexamethasone (Decadron), furosemide (Lasix), lithium, lidocaine, morphine, propranolol, statins, and succinylcholine.
    Test Tube Needed
    • Red top tube
    • Avoid IM injections in patients with cardiac disease.  These injections may falsely elevate the total CK level.
    • Collect a venous blood sample.  This is usually done initially and 12 hours later, followed by daily testing for 3 days, and then at 1 week.
    • Rotate the venipuncture sites. 
    • Avoid hemolysis. 
    • Record the date and time of any IM injection. 
    • Record the exact time and date of venipuncture on each laboratory slip. This aids in the interpretation of the temporal pattern of enzyme elevations.
    • Apply pressure or a pressure dressing to the venipuncture site and observe the site for bleeding.
    What To Tell Patient Before & After
    • Explain the procedure to the patient. 
    • Discuss with the patient the need and reason for frequent venipuncture in diagnosing MI. 
    • Tell the patient that no food or fluid restrictions are necessary.

    Pagana K, Pagana TJ eds. Mosby's Manual of Diagnostic and Laboratory Tests. 5th Ed.  St. Louis, Missouri. 2014.

MESH Terms & Keywords

  • Creatine Kinase, CK