What is a myoglobin test?
A myoglobin test measures the amount of myoglobin, a protein found in your skeletal muscles (the muscles attached to your tendons and bones) and heart muscles, in your blood or urine (pee).
Healthcare providers may use a myoglobin blood test to detect muscle damage. When your heart or skeletal muscles experience an injury, your muscle cells release myoglobin into your bloodstream. The level of myoglobin in your blood can rise very quickly with severe muscle damage, and healthcare providers typically measure it within a few hours following an injury.
Your kidneys filter out myoglobin from your blood and release it into your urine. Healthcare providers sometimes use a urine test to evaluate myoglobin levels if you’ve had extensive damage to your skeletal muscles (rhabdomyolysis). Urine myoglobin levels reflect the degree of muscle injury — the more myoglobin in your urine, the more severe the injury. Since myoglobin is toxic to your kidneys, a urine test can also assess the risk of kidney damage.
What is the function of myoglobin?
Myoglobin is a protein that’s found in your striated muscles, which includes skeletal muscles (the muscles attached to your bones and tendons) and heart muscles. Its main function is to supply oxygen to the cells in your muscles (myocytes).
All cells in your body need oxygen in order to function. They use oxygen to convert stored energy. Your skeletal muscles and heart muscles require a lot of oxygen and energy due to their constant use.
What is the difference between myoglobin and hemoglobin?
While both myoglobin and hemoglobin are responsible for carrying oxygen to certain tissues, they have different functions.
Hemoglobin is a protein found in red blood cells that gives those cells their red color. Its main function is to carry oxygen from your lungs to the rest of the cells in the tissues and organs of your body.
Myoglobin is mainly present in your striated muscles (the kind of muscles that you consciously move, like your arm and leg muscles), whereas hemoglobin is found in your bloodstream. Myoglobin only enters your bloodstream if you experience muscle damage. Like hemoglobin, myoglobin is the reason your muscle tissues have a reddish hue.
When would I need a myoglobin test?
Your healthcare provider may order a myoglobin blood test if you’re experiencing symptoms of severe damage to your muscles, such as from accidents that result in muscle trauma, or muscular dystrophy.
Symptoms of muscle injury or damage include:
While healthcare providers have used myoglobin blood tests along with troponin tests to help detect a heart attack early in the past, they now use myoglobin testing less frequently for this purpose. More recent studies have revealed that newer markers, such as troponin, are better for detecting heart attacks.
Your healthcare provider may order a urine myoglobin test if you have extensive damage to your skeletal muscles, resulting in the rapid breakdown of muscle (rhabdomyolysis), and if they suspect that you may have damage to your kidneys from excess myoglobin.
Your healthcare provider may also order either test if you have acute kidney failure without any clear cause.
Who performs a myoglobin test?
A healthcare provider called a phlebotomist usually performs blood draws, which include those for a myoglobin blood test, but any healthcare provider who is trained in drawing blood can perform this task. They then send the samples to a lab where a medical laboratory scientist prepares the samples and performs the tests on machines known as analyzers.
If your healthcare provider has ordered a urine myoglobin test, you can perform the procedure using the “clean catch” method to collect a urine sample. In some cases, your provider may insert a catheter into your urethra to collect a urine sample.
How do I prepare for a myoglobin test?
There are no special preparations for a myoglobin blood test or urine test.
What should I expect during a myoglobin test?
There are different processes for a urine myoglobin test and a blood myoglobin test.
Myoglobin blood test process
You can expect to experience the following during a myoglobin blood test, or blood draw:
- You’ll sit in a chair, and a healthcare provider will check your arms for an easily accessible vein. This is usually in the inner part of your arm on the other side of your elbow.
- Once they’ve located a vein, they’ll clean and disinfect the area.
- They’ll then insert a small needle into your vein to take a blood sample. This may feel like a small pinch.
- After they insert the needle, a small amount of blood will collect in a test tube.
- Once they’ve enough blood to test, they’ll remove the needle and hold a cotton ball or gauze on the site to stop the bleeding.
- They’ll then place a bandage over the site, and you’ll be finished.
The entire procedure usually takes fewer than five minutes.
Myoglobin urine test process
In most cases, you’ll perform a myoglobin urine test using the “clean catch” method, which is intended to help prevent contamination of your urine sample with cells from your genitals. You or your healthcare provider can also collect a urine sample using a catheter.
For the clean catch method, your provider will give you a specimen cup, sterile wipes and specific instructions for collecting your urine sample. Your healthcare provider will tell you what to do with your urine sample after you’ve collected it. It’s important to wash your hands with soap and water before you collect the sample.
If you have a labia, use the following steps to get a clean catch urine sample:
- Start by sitting on the toilet with your legs spread apart.
- Using two fingers, spread your labia open. Then, use one sterile wipe to clean the inner folds of your labia, wiping from front to back.
- Use another sterile wipe to clean over your urethra, the opening where urine flows out of your body.
- Urinate a small amount into the toilet.
- Stop the flow of urine, and hold the specimen cup a few inches away from your urethra.
- Urinate into the cup, filling it about half full or however full your healthcare provider instructed you to.
- Finish urinating into the toilet.
If you have a penis, use the following steps to get a clean catch urine sample:
- Use a sterile wipe to clean the head of your penis. If your penis is uncircumcised, first pull back your foreskin to ensure a thorough cleaning.
- Urinate a small amount into the toilet.
- Stop the flow of urine, and hold the specimen cup a few inches from your urethra, the opening where urine flows out of your penis.
- Fill your specimen cup about half full or however full your healthcare provider instructed you to.
- Finish urinating into the toilet.
What should I expect after a myoglobin test?
After your healthcare provider has collected your blood sample, they’ll send it to a laboratory for testing. Once the test results are back, your healthcare provider will share the results with you.
Once you have collected your urine sample, your healthcare provider may examine the sample immediately and run tests on it. Many urine tests provide results within seconds or minutes. If your urine sample needs to be examined under a microscope, your healthcare provider will likely send it to a laboratory for testing.
What are the risks of a myoglobin test?
Blood tests are a very common and essential part of medical testing and screening. There’s very little risk to having blood tests. You may have slight tenderness or a bruise at the site of the blood draw, but this usually resolves quickly.
The clean catch method of urine sample collecting for a urine myoglobin test doesn’t have any risks. It’s a painless and non-invasive test. If you or your healthcare provider use a catheter to collect a urine sample, though, there’s a risk of infection. It may also cause pain or discomfort.
When should I know the results of my myoglobin test?
Since healthcare providers usually order myoglobin tests for extreme or emergency situations, such as extensive muscle trauma or heart attacks, they’ll likely have the test results within minutes or hours.
If you’re getting a myoglobin test as a part of routine testing, such as to monitor a chronic muscular condition, you’ll likely get your test results back within one to two days, though it could take longer.
Results and Follow-Up
What do the results of a myoglobin test mean?
Blood and urine test reports, including myoglobin blood and urine test reports, usually provide the following information:
- The name of the blood or urine test or what was measured in your blood or urine.
- The number or measurement of your blood or urine test result.
- The normal measurement range for that test.
- Information that indicates if your result is positive or negative, normal or abnormal or high or low.
What are normal myoglobin levels?
Normal ranges for myoglobin blood tests can vary slightly from lab to lab. Always check the given reference range on your lab report test results. In general, though, the normal myoglobin ranges are:
- For men and people assigned male at birth: Less than 91 ng/mL (nanograms per milliliter).
- For women and people assigned female at birth: Less than 63 ng/mL.
Myoglobin is normally very low or undetectable in urine. A normal myoglobin urine result is sometimes reported as “negative.”
What does a high myoglobin level mean?
Elevated levels of myoglobin in your blood or urine have slightly different indications. While high myoglobin levels can indicate muscle or heart damage, the test cannot diagnose the cause of the damage or where it’s occurring in your body.
High levels of myoglobin in blood
Having elevated levels of myoglobin in your blood usually indicates that you’ve experienced very recent skeletal muscle or heart muscle damage. The following situations or conditions can result in elevated levels of myoglobin in your blood:
- Accidents that result in muscle trauma.
- Excessive physical activity in untrained people.
- Any muscle disease, such as muscular dystrophy.
- Inflammation of skeletal muscles (myositis).
- Skeletal muscle ischemia (oxygen deficiency).
- Heart attack (myocardial infarction).
- Malignant hyperthermia (this is very rare).
Very high levels of myoglobin in your blood may be due to rhabdomyolysis, a condition that involves a rapid breakdown of muscle tissue. Rhabdomyolysis can be caused by a serious injury to your muscles from several different sources, including:
- Trauma and crushing injuries, such as car accidents.
- Severe electrical shock.
- Serious and/or extensive burns.
- A blood clot that blocks blood flow to tissues.
- Exposure to toxins such as heavy metals, snake venom or carbon monoxide.
- Viral infections such as HIV, influenza (flu) and Streptococcus (strep) — this more commonly occurs in children than adults.
- Certain drugs, such as drugs of abuse (alcohol, heroin and cocaine), antibiotics, corticosteroids, lithium, statins and others.
Rhabdomyolysis can lead to damage to your kidneys and needs to be treated in a hospital.
High levels of myoglobin in urine
If you have high levels of myoglobin in your urine, it usually indicates that you have extensive damage to your skeletal muscles, resulting in the rapid breakdown of muscle (rhabdomyolysis).
The higher the myoglobin level in your urine, the more at risk you are for kidney damage since myoglobin is toxic to your kidneys. If you have high amounts of myoglobin in your urine, your healthcare provider will provide treatment to try to minimize kidney damage.
What does a low myoglobin level mean?
As the normal reference range for myoglobin blood levels begins at zero, having “low” myoglobin levels has no medical significance. Similarly, normal urine has no or very small amounts of myoglobin.
When should I call my doctor?
If you’re experiencing symptoms of extensive muscle damage, such as intense muscle pain, fever and/or vomiting, it’s important to call your healthcare provider or go to the nearest hospital.
If you’re experiencing symptoms of a heart attack, such as chest pain and feeling lightheaded, call 911.
A note from Cleveland Clinic
Seeing an abnormal test result can be stressful, but know that having an elevated myoglobin level doesn’t necessarily mean you have a medical condition and need treatment. Your healthcare provider will let you know if you need to undergo further tests to determine the cause of the elevated level. Don’t be afraid to ask your healthcare provider questions. They’re there to help you.
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