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Test Code MYGLU Myoglobin, Random, Urine

Reporting Name

Myoglobin, Random, U

Useful For

Confirming the presence of a myopathy

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Specimen Required


Supplies: Urine Myoglobin Transport Tube (T691)

Container/Tube: Plastic, 5-mL urine myoglobin transport tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect a preservative-free, random urine specimen.

2. If specimen is at ambient temperature, aliquot the urine to a urine myoglobin transport tube within 1 hour of collection. Refrigerate specimen.

3. If specimen is at refrigerate temperature, aliquot the urine to a urine myoglobin transport tube within 2 hours of collection.

Additional Information: Urinary myoglobin is highly unstable unless alkalinized with sodium carbonate preservative.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated 7 days MYOGLOBIN TRANSPORT TUBE

Reference Values

0-24 mcg/L

Reference values have not been established for patients younger than 18 years; however myoglobin is not expected to be detectable in urine.

Day(s) Performed

Monday through Sunday

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83874

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MYGLU Myoglobin, Random, U 2641-9

 

Result ID Test Result Name Result LOINC Value
MYGLU Myoglobin, Random, U 2641-9

Clinical Information

Myoglobin is a small 17.8 kDa oxygen-binding heme protein, present in striated muscle to carry and store oxygen in muscle cells. By virtue of its small size, myoglobin is readily filtered by the glomerulus and catabolized by endocytosis and proteolysis in the proximal tubule. Healthy subjects normally have low concentrations (less than 5%) of protein appearing in the urine. Injury to skeletal or cardiac muscle results in a large release of myoglobin into systemic circulation within a few hours, which can overwhelm tubular resorption causing notable quantities of myoglobin to appear in urine giving it a red-brown appearance. The presence of myoglobin in the urine is a risk factor for developing acute kidney injury. Myoglobin concentration declines rapidly, with a serum half-life of 2 to 3 hours and has been studied for its ability to predict acute kidney injury.

 

High concentrations appear very rapidly in the urine in various conditions, including some metabolic diseases.

Conditions that can lead to rhabdomyolysis associated with myoglobinuria include:

-Trauma or crush injury

-Heatstroke, hypothermia, malignant hyperthermia

-Seizures, strenuous exercise, prolonged immobility

-Hypoxic injury

-Metabolic disturbances in electrolyte concentrations

-Genetic disorders that lead to muscle cell breakdown

-Infections

-Drugs or toxins

 

The presence of myoglobin in the urine can indicate serious muscle injury, which is a risk factor for developing acute kidney injury. Rhabdomyolysis is often confirmed and monitored by measuring serum creatine kinase, electrolytes, kidney function, and urine tests for protein and blood. Myoglobin will give a positive reaction with hemoglobin test strips, though red blood cells will be absent upon microscopic review.

Interpretation

Increased excretion of urinary myoglobin is suggestive of one of the disorders or conditions listed in Clinical Information.

 

Most clinically significant elevations are elevated 2 to 10 times normal.

Report Available

1 to 2 days

Reject Due To

Use of any transport tube other than urine myoglobin transport tube Reject

Method Name

Electrochemiluminescent Immunoassay (ECLIA)

Secondary ID

621087

Specimen Retention Time

7 days