Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

MYOU
9274
FMYOP
91545
myoglobin reflects a balance between intravascular release of myoglobin from muscle and renal
clearance. Previously serum myoglobin had been advocated as a sensitive marker for early acute
myocardial injury (eg, acute myocardial infarction [AMI]). However more recent studies indicate that
other newer markers (eg, troponin) provide superior diagnostic utility in detecting early myocardial injury.
Elevation of serum myoglobin may occur as a result of muscle trauma, resuscitation, myopathies, AMI,
shock, strenuous body activity, or decreased elimination during renal insufficiency. Extreme elevations
occur in rhabdomyolysis.
Useful For: Accessing muscle damage from any cause
Interpretation: Elevated myoglobin levels are seen in conditions of acute muscle injury.
Reference Values:
0.00-0.09 mcg/mL
Reference values apply to all ages.
Clinical References: Eggers KM, Oldgren J, Nordenskjold A, Lindahl B: Diagnostic value of
serial measurement of cardiac markers in patients with chest pain: limited value of adding myoglobin to
troponin I for exclusion of myocardial infarction. Am Heart J 2004;148(4):574-581
Myoglobin, Urine
Clinical Information: Myoglobin is the oxygen-binding protein of striated muscle. Injury to
skeletal or cardiac muscle results in the release of myoglobin. High concentrations appear very rapidly
in the urine in various conditions including some metabolic diseases. Conditions associated with
myoglobinuria include: -Hereditary myoglobinuria -Phosphorylase deficiency -Sporadic myoglobinuria
-Exertional myoglobinuria in untrained individuals -Crush syndrome -Myocardial infarction
-Myoglobinuria of progressive muscle disease -Heat injury(1,2) Urine myoglobin increases with muscle
necrosis, but the clinical consequences are variable. Therefore, myoglobin can confirm a clinical
diagnosis of myopathy, but an elevated urine excretion of myoglobin is not specific for a clinical
disorder.(1,2) In acute renal failure, an elevated urinary myoglobin can suggest a potential cause and,
consequently, may indicate appropriate treatment courses. Urine myoglobin cross-reacts with standard
urine dipstick tests for hemoglobin (false-positive). If the dipstick is positive for hemoglobin but the
urine contains no or few RBCs, the urine myoglobin test may help confirm or rule out hemoglobinuria.
Useful For: Confirming the presence of a myopathy associated with any 1 of the above disorders
May suggest a myopathic cause for acute renal failure Follow-up testing for specimens with positive
urine hemoglobin results by the dipstick method
Interpretation: Increased excretion of urinary myoglobin suggests the disorders listed above. Most
clinically significant elevations are elevated 2 to 10 times normal. Visual pigmenturia occurs at
myoglobin concentrations is about 160 times normal (approximately 4 mcg/mL). Renal toxicity depends
on multiple factors such as renal perfusion and degree of acidity of urine.
Reference Values: