Erythropoietin (EPO) test
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◉ Erythropoietin (EPO) blood test
Erythropoietin (EPO) is a hormone that is mainly produced by the kidneys and stimulates the production of red blood cells by the stem cells present in the bone marrow.
EPO is essential for maintaining normal levels of oxygen in the blood and preventing anemia, and it can also be synthesized and used as a treatment for some forms of anemia.
The EPO test is primarily used in the field of sports medicine to detect the misuse of exogenous EPO, which is a prohibited substance in competitive sports. By measuring EPO levels, the test can help identify athletes who may be using synthetic EPO to enhance their performance illegally.
◉ What is the importance of Erythropoietin in the body?
- Chemically, erythropoietin is a protein with an attached sugar (a glycoprotein). It is one of a number of similar glycoproteins that serve as stimulants for the growth of specific types of blood cells in the bone marrow.
- The kidneys and liver produce erythropoietin when oxygen levels in the cells are low (hypoxemia). The hormone then stimulates the bone marrow, which, in turn, makes more red blood cells.
- EPO initiates the synthesis of hemoglobin, the molecule within red blood cells that transports oxygen.
- EPO helps regulate the number of red blood cells by stimulating the bone marrow to make more when the oxygen levels are low, and by protecting them from destruction.
- EPO also has other functions, such as supporting the growth of blood vessels and the repair of tissues.
◉ What is the purpose of the Erythropoietin test?
- The purpose of an erythropoietin test is to measure the amount of erythropoietin (EPO) in your blood, additional to that it aids in distinguishing between primary and secondary polycythemia.
- The EPO test has clinical applications in the diagnosis and management of certain medical conditions. It can be used to evaluate patients with anemia (low red blood cells) or polycythemia (high red blood cells), kidney disease, or other disorders affecting red blood cell production. Monitoring EPO levels can provide valuable information for determining the appropriate treatment and assessing the response to therapy.
◉ When do I need the test?
Your health care provider may order an erythropoietin test if you have the following signs or symptoms of:
- Shortness of breath.
- An increase in the heart rate.
- Joint pain.
- Chronic kidney disease.
- Bone marrow disorder.
- Decreased or increased red blood cell count.
- Anemia during pregnancy.
- Recombinant erythropoietin or rHuEPO abuse is quite common in endurance sports. The test is often done in professional athletes and long-distance runners to detect the presence of synthetic EPO in the blood.
◉ How can I prepare for the Erythropoietin test?
This test does not require any special preparation. However, you need to inform your health care provider if you are taking any particular medication, vitamins, supplements, herbs, or illicit drugs.
◉ What is the normal range of the Erythropoietin test?
The normal range of the erythropoietin test may vary depending on the laboratory and the method used, but generally the normal range is 2.6 to 18.5 milliunits per milliliter (mU/mL) or between 4 and 26 mU/mL.
You should consult your healthcare provider to interpret your test results and diagnose any underlying problem.
◉ High values of the Erythropoietin test
Causes
- Secondary Polycythemia: is an overproduction of red blood cells that occurs in response to an event such as chronic low blood oxygen level, such as in smoking, lung diseases, heart diseases, or living in a high-altitude environment where air oxygen levels are lower.
- EPO abuse: Raised levels of Erythropoietin in athletes indicate erythropoietin abuse (doping). EPO doping can boost the number of red blood cells and there by increased availability of oxygen to the muscles. This can help the athlete with increased performance ability and endurance. Blood doping is illegal especially in professional sports. Professional athletes are asked to take this test to find out if they are violating the anti-doping law. This can lead to dangerously high levels of red blood cells and increased risk of blood clots, stroke, and heart attack.
- In severe cases of anemia, EPO levels in the blood may be a thousand times higher than normal.
- In rare cases, certain tumors can also cause your kidneys to release inappropriately excessive EPO.
Symptoms
- Weakness
- Fatigue
- Headache
- Joint pain
- Dizziness
- Blurred vision
- Flushed skin
- Increased risk of blood clots, stroke, and heart attack
- High blood pressure
- Chest pain
- Shortness of breath
- Nausea
- Fever
- Swelling of the legs or ankles
- Redness of the face and hands
- Bleeding gums or nose
- Abdominal pain or fullness
- Night sweats
- Weight loss
- Itching, especially after a warm bath or shower
◉ Low values of the Erythropoietin test
Low values of the erythropoietin (EPO) test indicate that the body is producing too few red blood cells, a condition known as anemia. This can happen when the kidneys are damaged and cannot produce enough EPO, or when the bone marrow does not respond well to EPO.
Causes
- Polycythemia Vera: Primary polycythemia can also lead to low levels of EPO. It is a type of blood cancer that causes your bone marrow to make too many red blood cells due to a genetic mutation. It causes low EPO levels because your kidneys sense that you have enough red blood cells, so they don’t produce as much EPO.
- Chronic kidney disease (CKD): This is the most common cause of low EPO levels. CKD impairs the ability of the kidneys to make EPO, leading to anemia.
- Bone marrow disorders: These are diseases that affect the production or function of the blood cells in the bone marrow, such as aplastic anemia, myelodysplastic syndromes, or leukemia. These disorders may reduce the response of the bone marrow to EPO, resulting in anemia.
- Iron deficiency: This is a condition in which the body does not have enough iron to make hemoglobin, the protein that carries oxygen in the red blood cells. Iron deficiency may impair the production of EPO, leading to anemia.
Symptoms
- Weakness
- Fatigue
- Pale skin
- Shortness of breath
- Chest pain
- Dizziness
- Headache
- Cold hands and feet
- Irregular heartbeat.
Some of the related analytical tests to the erythropoietin test are:
Complete blood count (CBC): This is a blood test that measures the number and characteristics of different blood cells, including red blood cells, white blood cells, and platelets. CBC can help diagnose anemia, polycythemia, infection, inflammation, and other blood disorders that may affect EPO levels.
Hemoglobin: This is a blood test that measures the amount of hemoglobin, the protein that carries oxygen in the red blood cells. EPO is inversely proportional to hemoglobin levels, meaning that low hemoglobin levels stimulate EPO production and high hemoglobin levels inhibit EPO production.
Reticulocyte count: This is a blood test that measures the number of reticulocytes, which are immature red blood cells. Reticulocyte count is an important indicator of the bone marrow's response to EPO and the rate of red blood cell production.
Iron studies: These are a group of blood tests that measure the levels of iron, total iron binding capacity, ferritin, and transferrin in the blood. Iron is an essential component of hemoglobin and is needed for EPO to stimulate red blood cell production. Iron deficiency can cause low EPO levels and anemia.
◉ Conclusion
In conclusion, the EPO test serves as a valuable tool in both sports medicine and clinical settings. It plays a critical role in detecting EPO misuse in competitive sports and aiding in the diagnosis and management of certain medical conditions. However, it is essential to ensure the proper administration and interpretation of the test results to maintain its accuracy and reliability.