The myoglobin test is done to check the amount of this protein in the blood in order to identify muscle and cardiac injuries. This protein is present in the heart muscle and other muscles in the body, providing the oxygen needed for muscle contraction.
Thus, myoglobin is not normally present in the blood, it is only released when there is an injury to a muscle after a sports injury, for example, or during a heart attack, in which the levels of this protein start to increase in the blood 1 to 3 hours after the infarction, peaks between 6 and 7 hours and returns to normal after 24 hours.
Therefore, in healthy people, the myoglobin test is negative, only being positive when there is a problem with any muscle in the body.
Myoglobin Functions
Myoglobin is present in muscles and is responsible for binding to oxygen and storing it until needed. Thus, during physical activity, for example, the oxygen stored by myoglobin is released to generate energy. However, in the presence of any situation that compromises the muscles, myoglobin and other proteins may be released into the circulation.
Myoglobin is present in all striated muscles of the body, including the cardiac muscle, and is therefore also used as a marker of cardiac injury. Therefore, the measurement of myoglobin in the blood is requested when there is a suspicion of a muscle injury caused by:
- Muscular dystrophy; Severe blow to the muscles; Muscle inflammation; Rhabdomyolysis; Convulsions; Infarction.
Although it can be used when a heart attack is suspected, the test most used today to confirm the diagnosis is the troponin test, which measures the presence of another protein that is only present in the heart and is not influenced by other muscle injuries. Learn more about the troponin test.
In addition, if the presence of myoglobin in the blood is confirmed and is in very high values, a urine test can also be done to assess kidney health, since very high levels of myoglobin can cause kidney damage, impairing its functioning..
How the exam is done
The main way to do the myoglobin test is by collecting a blood sample, however, in many cases, the doctor may also ask for a urine sample, since the myoglobin is filtered and eliminated by the kidneys.
For any of the exams, it is not necessary to do any kind of preparation, such as fasting.
What does high myoglobin mean
The normal result of the myoglobin test is negative or less than 0.15 mcg / dL, since in normal situations myoglobin is not found in the blood, only in the muscles.
However, when values above 0.15 mcg / dL are verified, it is indicated in the test that myoglobin is high, which is usually indicative of a problem in the heart or other muscles in the body and, therefore, the doctor may order more tests. such as electrocardiogram or cardiac markers to arrive at a more specific diagnosis.
High levels of myoglobin can also be a sign of other problems not related to the muscles, such as excessive alcohol consumption or kidney problems, so the result should always be evaluated with the doctor based on each person's history.
