The measurement of myoglobin in the urine is used to confirm muscle damage caused by any cause.
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Myoglobin is a protein similar to hemoglobin, contains a heme molecule, binds oxygen, and is found exclusively in striated and smooth muscle fibers and cardiac muscle. It acts as a short-term oxygen store. It is released into the interstitial fluid, with elevated serum levels detected 30-60 minutes after myocardial infarction or damage to any muscle tissue. Serum myoglobin is generally detected earlier than classical cardiac enzymes (total creatine kinase [CPK] or cardiac creatine kinase isoenzyme [CK-MB]). Because myoglobin is found in skeletal and cardiac muscle, it is not used to diagnose myocardial infarction. Tests used in conjunction with myoglobin for this purpose include troponin and CK-MB. Measuring serum myoglobin is not completely specific for diagnosing myocardial infarction.
Increased myoglobin levels are also seen after angina pectoris, chest trauma, cocaine use, electrocution accidents, post-exercise, intramuscular injection, muscle injury of any type, and renal failure. Within 8 hours of symptom onset, myoglobin's specificity for acute myocardial infarction is 98%, in contrast to CK-MB's 100% specificity.
Pathologies associated with myoglobinuria include:
- Hereditary myoglobinuria
- Sporadic myoglobinuria
- Phosphorylase deficiency
- Myoglobinuria of progressive muscle disease
- Myocardial infarction
- Collapse syndrome
- Injuries
Possible Interpretations of Pathological Values
- Increase: Acute alcohol intoxication with tremulous delirium, after cardiac arrest (possible increase), after open heart surgery, angina pectoris (possible increase), burns (severe), congestive heart failure (possible increase), dermatomyositis, arrhythmia (possible increase), glycogen and lipid storage diseases, hyperthermia, hypothermia, muscular dystrophy, myocardial infarction (elevated levels are detected 2-3 hours after infarction, peak at 6-9 hours and return to baseline within 36 hours), polymyositis, renal failure, rhabdomyolysis, shock, skeletal muscle injury or extreme muscle exertion, surgery, systemic lupus erythematosus (SLE), trauma, viral or bacterial infection. Medications: Ethyl alcohol (ethanol), statins, theophylline
Important Note
Laboratory test results are the most critical parameter for diagnosing and monitoring all pathological conditions. 70% and 80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be analyzed based on each case and family history, clinical findings, and the results of other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
