Lab Test: Myoglobin (Blood) Level
|
|---|
- Measurement of myoglobin to provide an early index of damage to the myocardium
- Can also be indicative of skeletal muscle breakdown
- Early evaluation of a patient with suspected acute myocardial infarction (MI).
- Disease or injury of skeletal muscle - used to assist in the diagnosis
- Myoglobin is an oxygen-binding protein found in cardiac and skeletal muscle. Measurement of myoglobin provides an early index of damage to the myocardium, such as occurs in myocardial infarction (MI) or reinfarction. Increased levels, which indicate cardiac muscle injury or death, occur in about 3 hours. Although this test is more sensitive than creatine phosphokinase (CPK) isoenzymes, it is not as specific. Trauma, inflammation, or ischemic changes to the non-cardiac skeletal muscles can also cause elevated levels of myoglobin. The benefit of myoglobin over CPK-MB is that it ay become elevated earlier in some patients. This may prove beneficial because thrombolytic therapy should be started within the first 6 hours after an MI.
- With
sudden and severe muscle injury, myoglobin can reach very high levels. Because myoglobin is excreted in the urine
and is nephrotoxic, urine levels must be monitored in patients with high
levels. To screen for myoglobin, the
routine urine dipstick for hemoglobin can be used.
- Increased levels may indicate:
- Skeletal muscle inflammation (myositis), malignant hyperthermia, muscular dystrophy, skeletal muscle ischemia, skeletal muscle trauma, rhabdomyolysis, or seizures
- Decreased levels may indicate:
- Polymyositis
- Creatine phosphokinase (CPK) - this test is very useful in the evaluation of MI.
- Lactic dehydrogenase (LDH) - this enzyme is also elevated when injury to muscle tissue occurs.
- Troponins - this test is a specific indicator of cardiac muscle injury.
- Recent administration of radioactive substances may affect test results determined by radioimmunoassay (RIA) methods. The recently administered radioisotope may interfere with testing.
- Increased myoglobin levels can occur after intramuscular (IM) injections. The injection can cause localized muscle injury and instigate an inflammatory response that could elevate myoglobin levels.
- Collect a venous blood sample.
- Apply pressure or a pressure dressing to the venipuncture site and assess the site for bleeding.
- Explain the procedure to the patient.
- Tell the patient that no fasting is required.
- Dadkhah S et al. The value of bedside cardiac multibiomarker assay in therapid and accurate diagnosis of acute coronary syndromes. Crit Pathw Cardiol 2007;6(2):76-84.
- Plebani M et al. Diagnostic strategies using myoglobin measurement in myocardial infarction. Clin Chim Acta 1998;272:69-77.
- Pagana K, Pagana TJ eds. Mosby's Manual of Diagnostic and Laboratory Tests. 5th Ed. St. Louis, Missouri. 2014.
Description
Indications & Uses
Clinical Application
Related Tests
Drug-Lab Interactions
Procedure
What To Tell Patient Before & After
References
MESH Terms & Keywords
|
|---|
|
