Erythropoietin is a vital hormone that stimulates the bone marrow to create red blood cells in the body.
These red blood cells help carry oxygen to other cells and tissues in the body through the bloodstream.
Having too much or too little erythropoietin in the body may contribute to problems with the blood. Doctors may therefore recommend tests to check erythropoietin levels in people with blood disorders such as anemia.
People with very low levels of erythropoietin may need injections of the hormone. These injections may successfully resolve the issue, but they do carry their own risks.
In this article, learn more about erythropoietin, including what it does and who is at risk of deficiency.
Erythropoietin is a hormone that plays an important role in making red blood cells.
The kidneys and liver produce erythropoietin when oxygen levels in the cells are low. The hormone then stimulates the bone marrow, which, in turn, makes more red blood cells.
It is normal for a small amount of erythropoietin to circulate in the blood, as this helps replenish the body’s natural blood stores.
Having higher levels of erythropoietin in the blood may be a sign that the body is not getting enough oxygen, however. This may be due to a low red blood cell count from anemia or another condition.
On the other hand, low levels of erythropoietin in the blood in someone with anemia may be a sign of other issues.
Erythropoietin helps keep the blood balanced by stimulating the marrow to make red blood cells. This is an important role, as all cells in the body need a fresh supply of blood and oxygen to stay healthy.
Without fresh red blood cells, the organs and tissues in the body may experience hypoxia, which is a lack of oxygen.
Hypoxia can alter the way the cells behave and may ultimately lead to illness or cell death in the area.
Erythropoietin also helps protect these blood cells once the body creates them.
Erythropoietin levels may vary slightly under normal circumstances, such as when a person moves to a higher altitude. However, some conditions may also interrupt the natural production of erythropoietin in the body.
For instance, anemia can make it difficult to maintain healthy red blood cells in the body.
People with anemia may have very high levels of erythropoietin in their blood, as the body is constantly trying to stimulate the marrow to make more red blood cells.
If a healthcare professional suspects that a person has a condition such as anemia, they may ask to take a blood sample to conduct an erythropoietin test.
Doctors will generally order an erythropoietin test only after the results of a complete blood count test come back abnormal.
An erythropoietin test measures the levels of erythropoietin in the blood. Doctors use the test to help them identify the underlying cause of anemia or the presence of another condition affecting the red blood cells.
For example, a doctor may order an erythropoietin test for someone with anemia. Anemia can have many different causes, ranging from iron or vitamin deficiencies to decreased blood cell life span or excessive bleeding.
An erythropoietin test can help a doctor identify the underlying cause of anemia in people who do not seem to have iron or vitamin deficiencies.
Doctors can also use erythropoietin tests when a person has a very high blood cell count. This is a condition called polycythemia. The erythropoietin test can identify the underlying cause and help doctors determine the next step.
Doctors may also order this test when investigating chronic kidney disease. Chronic kidney disease can reduce the body’s ability to create erythropoietin.
Erythropoietin tests may also help diagnose other conditions affecting the bone marrow, such as myeloproliferative disorders.
Average erythropoietin levels are around 5.8 to 9.9 international units per liter (IU/L) in males and 6 to 10.6 IU/L in females, according to research in the journal PLoS One. The average range can vary slightly depending on the laboratory conducting the test.
Significant changes in erythropoietin levels may help doctors identify the underlying cause of the issue. However, erythropoietin test results are not conclusive in every case, and doctors will often use other tests to help them identify and diagnose the underlying issue.
Test results that show that a person with anemia has high erythropoietin levels may be a sign of a bone marrow disorder. Low or normal erythropoietin levels in a person with anemia may be a sign of kidney disease.
In people with polycythemia, meanwhile, an erythropoietin test can help doctors identify the next diagnostic tools they need to use.
For instance, a person with polycythemia who has high erythropoietin levels may have a tumor or kidney condition causing them to produce too much erythropoietin.
A person with polycythemia and normal or low erythropoietin levels may have polycythemia vera, which is a rare type of blood cancer.
In any case, healthcare professionals will use additional tests to help clarify their results and confirm their diagnosis.
Blood transfusions using healthy, erythropoietin-rich blood may help treat some forms of anemia from chronic kidney failure.
Sometimes, however, a blood transfusion is not possible. When this is the case, a doctor may recommend synthetic injections called erythropoietin-stimulating agents (ESAs).
Doctors can deliver these drugs through an injection that activates the bone marrow in the same way that natural erythropoietin does, stimulating red blood cell production.
ESA injections can effectively treat some of the symptoms of kidney failure. In fact, the author of one 2013 article notes that ESA injections are by far most common in people with kidney failure.
Injections can help restore erythropoietin and red blood cell levels, but it may take time for levels to build up in the blood. It can take weeks, for example, before the person notices a reduction in their symptoms.
ESA injections may also help treat anemia due to other causes, such as:
- bone marrow conditions
- drug treatments
ESA injections also have the potential for abuse. Some athletes looking for a competitive edge may seek injections of synthetic erythropoietin to increase the red blood cells and oxygen levels in their body.
However, adding more erythropoietin to a healthy body can be dangerous and increase the risk of side effects.
Side effects and risks
ESA injections can help treat a number of conditions, but they do have the potential for side effects and risks.
Some common side effects of ESA injections include:
- pain at the injection site
- high blood pressure
More serious side effects are also possible. There may be an increased risk of:
- blood clots
- pulmonary embolism
- heart attack
- heart failure
Healthy people who abuse ESA injections may be more at risk of these side effects, as the unnecessary increase of red blood cells may make the blood thicker and more prone to clotting.
In some cases of use among people with cancer, the ESA may cause the tumor to grow. Therefore, these people may only receive ESAs for a short time to help prevent the symptoms of chemotherapy.
Also, ESA injections are costly, which can be a barrier to treatment in some cases.
During treatment, doctors will monitor a person’s blood levels regularly. They may adjust the dosage or treatment according to the results of blood tests to reduce the person’s risk of side effects.
Erythropoietin is a hormone that plays an important role in the production of red blood cells.
Abnormal erythropoietin levels may indicate an issue in the kidneys or bone marrow. Tests for erythropoietin levels can help doctors identify the underlying cause of blood conditions. Such causes include anemia.
In people with low erythropoietin levels due to kidney disease or other conditions, ESA injections may help treat the issue.
ESA injections carry some risks, however, as they make the blood thicker and more prone to clotting. Also, healthy people who abuse these injections may be at a higher risk of more serious complications.
Anyone who is uncertain about their diagnosis or treatment should talk to their doctor about all the treatment options before making any changes.