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Myoglobin Test

Formal name: Serum myoglobin
Related tests: CK, CK-MB, Troponin

At a Glance

Why Get Tested?

To determine whether muscle, particularly heart muscle, has been injured

When to Get Tested?

Every 2–3 hours after experiencing chest pain that is suspected to be due to a heart attack

Sample Required?

A blood sample taken from a vein in the arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Blood is being tested for the presence of myoglobin, which is a protein found in heart and other muscles. While haemoglobin brings oxygen to most of the body, myoglobin traps oxygen in muscle to allow muscle cells to work properly. When heart or other muscle is injured, myoglobin is released into the blood.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

How is it used?

Myoglobin is a small protein, and it leaks out of muscle cells soon after injury. Myoglobin concentrations within the blood start to rise within 1–3 hours of a heart attack or other muscle injury, reach their highest values by about 8–12 hours, and generally fall back to normal by about one day after injury occurred.

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When is it requested?

Myoglobin blood tests may be requested in people with chest pain who are suspected of having had a heart attack, particularly if the electrocardiogram (ECG) does not give clear cut results. (The ECG records the electrical changes in different parts of the heart muscle as it beats; the patterns change when heart muscle is damaged.

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What does the test result mean?

Looking for reference ranges?

When the myoglobin concentration in the blood rises, there has been very recent injury to the heart or other muscle tissue. If myoglobin does not increase at that point, a heart attack is very unlikely, unless the chest pain started more than a day before.

Because myoglobin is also found in other muscles, high concentrations usually require using other blood tests (such as troponin or CK–MB ) to help determine whether the damage was to heart or to other muscle. High concentrations within the blood can occur as a result of accidents, fits, surgery, or any muscle disease.

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Is there anything else I should know?

Increased myoglobin levels can occur after injections into muscles or strenuous exercise. Because the kidneys remove myoglobin from the blood, myoglobin levels may be high in persons whose kidneys are failing. Rarely, heavy alcohol abuse and certain drugs can cause muscle injury and increase myoglobin levels in the blood.

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Common Questions

1.  What does heart attack mean?

Heart attack means that some of the muscle in your heart has died. A medical term for this is myocardial infarction. Most commonly, a heart attack starts with a kind of heavy pressure or pain in the chest, often extending into the neck or left arm. You may have trouble catching your breath, or you may feel weak and break into a cold sweat.

A heart attack usually occurs because one of the blood vessels (called coronary arteries) that bring blood to your heart muscle is blocked. This usually happens when a blood clot forms in a blood vessel that is already partially blocked. The partial blockage, which happens gradually over many years, is usually caused by too much fat layered in the wall of the blood vessel (this is often called hardening of the arteries—the medical term for this is atherosclerosis).

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2.  If I have chest pain, does that mean I am having a heart attack?

Many other problems can cause chest pain, and it is not always possible to tell just from the type of chest pain whether or not you are having a heart attack. Many people have chest pain from straining the muscles in their chest, and chest pain can occur with some lung problems. Chest pain can be a warning sign of hardening of the arteries of the heart (coronary artery disease or CAD).

Chest pain that occurs during exercise, hard work, or at times of stress, lasts for a few minutes and goes away with rest is called angina. If the pain lasts longer than just a few minutes, especially if it occurs when you are resting, seek immediate medical attention.

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3.  What if I’m not sure I’m having a heart attack?

If you have prolonged chest pain, especially if it does not go away with rest— or if you have been told you have angina, and the drugs you were prescribed do not ease the pain, seek immediate medical attention. Many people who have had a heart attack die without ever having tried to call an ambulance or get to a hospital.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.