Myoglobin,Urine (MYO) |
EPIC Test Name
MYOGLOBIN, URINEEPIC Code
LAB412Specimen Requirements
Urine | |
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Minimum Volume: | 1.0 mL |
Collection: | Collect using standard laboratory procedures |
Transport: | Room Temperature ASAP |
Stability: | Room Temperature: 1 day at 15-25 degrees C Refrigerated: 7 days at 2-8 degrees C |
Container: | Urine cup |
Methods
Peroxidase activityTurnaround Time
Specimen | Turnaround Time | Frequency |
---|---|---|
Urine | Routine: 4 hours | 24/7 |
Reference Ranges
Peroxidase activity
All Range |
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Negative |
Clinical Indications
Myoglobin is a heme-containing protein (MW 17.8 kDa), for carrying and storage of oxygen in muscle cells. Normally, following glomerular filtration, myoglobin is eliminated by endocytosis and proteolysis in the proximal tubule, and only less than 5% of filtered protein appears in the urine.In event of muscle injury or damage, e.g., rhabdomyolysis, large amount of myoglobin that is released into the blood can saturate the tubular re-absorptive capacity and appear in the urine causing red-brown’s appearance (>200 times normal, or about 4000 mcg/L). Further, myoglobin self can cause acute tubular necrosis. Renal toxicity depends on multiple factors such as renal perfusion and degree of acidity of urine.
For urine analysis, myoglobin can react with the reagent strip assays that are designed for detecting hemoglobin in urine. The urine myoglobin test procedure used in the laboratory employs a step to remove hemoglobin in the urine sample prior to the analysis using the reagent strip.
It is worth to note that an increase in serum creatine kinase activity not attributable to a cardiac source can be a better indicator of rhabdomyolysis. Urinary myoglobin concentration does not provide useful prognostic information in this setting.
Additional Information
• DO NOT collect urine sample with acid preservative. Urine samples collected with acid as preservative should be rejected due to interference with analyte integrity.• Urine samples should be collected with sodium carbonate to alkalize the sample, due to instability urinary myoglobin.
• Store urinary samples at 4 celsius, DONOT freeze urine sample, myoglobin does not withstand freezing even when pH is raised with sodium carbonate.
Performed
Lab |
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Chemistry - Downtown |
Interpretative Information
Increased excretion of urinary myoglobin is indicative of a disorder of followings:• Hereditary myoglobinuria
• Phosphorylase deficiency
• Sporadic myoglobinuria
• Exertional myoglobinuria in untrained individuals
• Crush syndrome
• Myocardial infarction
• Myoglobinuria of progressive muscle disease
• Heat injury
Clinically significant elevations are mostly < 2 times normal.
CPT
83874LOINC
2640-1References
1. RA Zager: Rhabdomyolysis and myohemoglobinuric acute renal failure. Kidney Int. 1996;49:314-26. PMID 88218132. R Beetham: Biochemical investigation of suspected rhabdomyolysis. Ann Clin Biochem. 2000;37:581-7. PMID 11026512
3. Rowland LP: Myoglobinuria. Can J Neurol Sci. 1984;11:1-13
4. Tonin P, Lewis P, Servidei S, DeMauro S: Metabolic causes of myoglobinuria. Ann Neurol. 1990;27:181-5.
5. Dawley C: Myalgias and myopathies: rhabdomyolysis. FP Essent. 2016;440:28-36.
6. Nance JR, Mammen AL: Diagnostic evaluation of rhabdomyolysis. Muscle Nerve. 2015;51(6):793-810. doi: 10.1002/mus.24606