|Values are valid only on day of printing.|
Confirming the presence of a myopathy associated with any 1 of the disorders listed in Clinical Information
May suggest a myopathic cause for acute renal failure
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:
-Exertional myoglobinuria in untrained individuals
-Myoglobinuria of progressive muscle disease
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.
In acute renal failure, an elevated urinary myoglobin can suggest a potential cause and, consequently, may indicate appropriate treatment courses.
< or =21 mcg/L
Increased excretion of urinary myoglobin suggests the disorders listed in Clinical Information.
Most clinically significant elevations are elevated 2 to 10 times normal.
Visual pigmenturia occurs at myoglobin concentrations about 160 times normal (approximately 4,000 mcg/L).
Renal toxicity depends on multiple factors such as renal perfusion and degree of acidity of urine.
Urine collected with acid as preservative will not be valid because acid interferes with analyte integrity.
Urinary myoglobin deteriorates rapidly unless stabilized immediately after collection by alkalizing with Na2CO3.
Urinary myoglobin does not withstand freezing even when pH is raised with Na2CO3.
1. Rowland LP: Myoglobinuria. Can J Neurol Sci 1984;11:1-13
2. Tonin P, Lewis P, Servidei S, DeMauro S: Metabolic causes of myoglobinuria. Ann Neurol 1990;27:181-185