Myoglobin
Overview
Myoglobin measures an oxygen-binding heme protein found predominantly in cardiac and skeletal muscle cells that facilitates oxygen storage and transport within muscle tissue. During muscle injury, myoglobin is released into circulation where it can cause renal toxicity due to its rapid filtration and precipitation in renal tubules. Elevated levels indicate rhabdomyolysis, myocardial infarction, or severe muscle trauma; low levels have no clinical significance. Clinically, myoglobin testing provides early detection of muscle injury but lacks cardiac specificity compared to troponins.
Clinical Use Cases
- Early diagnosis of rhabdomyolysis and acute kidney injury risk assessment.
- Supporting diagnosis of acute myocardial infarction (early marker).
- Monitoring muscle damage after trauma, surgery, or strenuous exercise.
- Evaluating drug-induced myotoxicity (statins, colchicine).
Specimen Types
- Serum.
- Plasma.
- Urine (for myoglobinuria detection).
Measurement Methods
- Immunoturbidimetric assay.
- Enzyme-linked immunosorbent assay (ELISA).
- Rapid point-of-care immunochromatographic tests.
Test Preparation and Influencing Factors
- No special preparation; collect promptly after suspected injury.
- Hemolysis interferes with serum assays (falsely elevates).
- Renal impairment delays myoglobin clearance.
- African Americans may have higher baseline levels due to genetic variants.
Synonyms
- Muscle hemoglobin.
- Myo.