Myoglobin Test-Why am I having this test?

Myoglobin is a type of protein that is found in the muscles of the body. Muscles release myoglobin into the blood after they are injured. You may have a myoglobin test to help diagnose:

• A heart attack. A heart attack may not cause recognizable symptoms in some cases, but the myoglobin test can help determine whether you are having or have recently had a heart attack.
• A muscle disease or injury.
• Certain heart conditions.

What is being tested?

This test measures the amount of myoglobin in the blood or urine. Myoglobin is found in the heart (cardiac) muscles and in muscles that connect to bones (skeletal muscles). It is released in response to muscle damage, such as damage from inflammation, an injury, or a heart attack.

What kind of sample is taken?

A blood sample or a urine sample may be required for this test. A blood sample is usually collected by inserting a needle into a blood vessel.

How are the results reported?

If you are having a blood test:

• Your results will be reported as a value that indicates how much myoglobin is in your blood. This will be given as micrograms of myoglobin per liter of blood (mcg/L).
• Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, a common normal reference range is 0–90 mcg/L.

If you are having a urine test, your results will be reported as positive or negative for myoglobin. Positive means that there is myoglobin in your urine. Negative means that there is no myoglobin in your urine.

What do the results mean?

A blood test result that is within the reference range is considered normal. This means that you have a normal amount of myoglobin in your blood. A negative urine test result is also considered normal.

A positive urine test result or a blood test result that is higher than the reference range means that you have an abnormally high amount of myoglobin in your blood. This may be caused by:

• A recent seizure.
• A heart attack.
• Your body attacking your newly transplanted heart (rejection).
• A condition or injury that causes muscle to break down.
• Muscle inflammation (myositis).
• Vigorous exercise.

A large amount of myoglobin can cause damage to your kidneys.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• Myoglobin is a type of protein found in muscles of the body.
• Myoglobin is found in the heart (cardiac) muscles and in muscles that connect to bones (skeletal muscles). It is released in response to muscle injury.
• You may have the myoglobin test to help diagnose a disease or injury of muscle, or to help diagnose a heart attack.
• A blood test result within the reference range is considered normal. A negative urine test result is also considered normal.