Your doctor can use a myoglobin test to detect the amount of the protein
myoglobin in your urine. Your doctor might order this test for several reasons.
They may order it if they think your muscle tissues have been damaged. It can
help them determine your risk of kidney damage from muscle injury. If you
experience sudden kidney failure, it can also help them understand why because myoglobin
can cause significant damage to your kidneys.
What is myoglobin?
Myoglobin is a type of protein in your body. It’s naturally present in your heart
and skeletal muscle. Skeletal muscle is what we traditionally think of as muscle
throughout the body. It’s essential for the proper functioning of your
musculoskeletal system and body movements.
All of your muscles require oxygen to perform normal body movements, such as
sitting, standing, walking, or performing numerous daily activities. Your
muscles also require oxygen for more demanding activities, including exercise.
Myoglobin is a protein that binds to oxygen recruiting it into your muscle
fibers from the blood stream. This helps make oxygen available for your heart
and skeletal muscles to carry out their essential functions.
If you’re healthy, myoglobin will remain within your muscle. If your muscle
is damaged, it will release myoglobin into your bloodstream. When it’s released
into your bloodstream, your kidneys filter it out and excrete it from your body
through your urine.
How is a myoglobin urine test performed?
A urine myoglobin test requires a urine sample. The test doesn’t carry any
risk. It shouldn’t cause any amount of pain.
You may need to take some steps to prepare beforehand. If you’re a man, your
doctor will probably ask you to wipe the head of your penis before providing
your urine sample. If you’re a woman, your doctor will probably ask you to wash
your genital area with warm, soapy water, making sure to rinse the area
thoroughly afterward. You probably won’t need to fast or stop taking medications
before providing your sample.
After that, you simply need to catch a small amount of urine in a container
provided by your doctor. A midstream sample is often preferable. This means you
should urinate a small amount before you start collecting your urine in the
After you place the lid on the container, wash your hands thoroughly. Your
doctor will send it to a laboratory for testing.
What do the results mean?
The lab will analyze your sample to determine whether your urine contains
myoglobin. If it does contain myoglobin, the lab will determine the
No significant amount of myoglobin should be present in your urine. If
there’s no myoglobin in your urine, it’s considered a normal result. It’s also sometimes
known as a negative result.
Possible causes of abnormal results
If a measurable amount of myoglobin is in your urine sample, it’s considered
an abnormal result. Abnormal results have a number of possible causes:
For example, myoglobin may appear in your urine if any of the following
- Your skeletal muscles have been damaged, for instance,
by accidents or surgery. Drug use, alcohol use, seizures, prolonged
vigorous exercise, and low phosphate levels can also damage your skeletal
- You have muscular dystrophy or another type of disease
or disorder that causes muscle damage.
- You’ve had a heart attack. A heart attack damages or
destroys your cardiac muscle, which results in the release of myoglobin.
Malignant hyperthermia is an
extremely rare condition that can cause muscle contracture or rigidity and myoglobin
in the urine. A serious adverse reaction to certain anesthesia medications
causes it. Most people who develop this condition have a genetic mutation that
makes them susceptible to getting it.
What will happen after the test?
If myoglobin is in your urine, your doctor may order additional tests to
determine the underlying cause and prescribe an appropriate treatment plan. The
treatment for a heart attack will clearly be different than that for extensive
trauma to your skeletal muscles.
Your doctor will probably monitor your kidney function closely since myoglobin
can damage your kidneys. They’ll use additional tests to do this, such as the test
for blood urea nitrogen, the creatinine test, or urinalysis.
Ideally, your doctor will be able to treat your underlying condition and
prevent any lasting damage to your kidneys. Ask your doctor for more
information about your specific diagnosis, treatment plan, and long-term