Erythropoietin Test

The hormone erythropoietin (EPO) is predominantly produced by the kidney and liver. Red blood cells (RBCs) transport oxygen from the lungs to the rest of the body. EPO plays an important role in RBC production. The test measures the level of erythropoietin in the blood.

The kidneys produce and release erythropoietin into the bloodstream. Erythropoietin forms in response to low blood oxygen levels (hypoxaemia). The amount of erythropoietin released depends on the amount of oxygen in the blood and on kidney functioning.

EPO in the bone marrow increases red blood cell synthesis. The hormone is active for a brief time. After its function, EPO gets eliminated in the urine. The kidneys reduce EPO production as blood oxygen levels return to normal or near normal.

In conditions where there is damage to the kidney and kidneys don't create enough erythropoietin, the body produces too few RBCs. Reduced RBC in the blood leads to anaemia.

Erythropoietin maintains the blood balance by increasing the production of red blood cells in the bone marrow. The erythropoiesis is a vital function since all cells in the body require a constant supply of blood and oxygen to remain healthy.

Without new red blood cells, the body's organs and tissues may suffer from hypoxia or a shortage of oxygen. Hypoxia can cause cells to behave differently, which leads to sickness or cell death in the area.

If the bone marrow does not respond to the stimulation by EPO, the person may become anaemic. The anaemia might happen as a result of some bone marrow problems or chronic diseases like rheumatoid arthritis.

In conditions that reduce the amount of oxygen, such as lung illness, the body may generate more EPO as a compensatory mechanism. People residing at high altitudes and chronic cigarette smokers may have greater EPO levels.

RBCs production increases with too much erythropoietin, which can happen with some benign and malignant kidney tumours. Erythropoietin values increase in several other cancers (polycythemia or erythrocytosis). Increased RBCs can increase blood viscosity, which can cause high blood pressure (hypertension), blood clots (thrombosis), heart attack or stroke.

The primary purpose of the erythropoietin (EPO) test is to determine the cause of anaemia. A complete blood count (CBC) with abnormal results, such as a low red blood cell (RBC) count, low haemoglobin and low haematocrit, is followed up with an EPO test. These tests aid in the diagnosis of anaemia and provide information about the underlying cause.

Erythropoietin testing is done to see if a lack of EPO is causing or exacerbating anaemia.

An erythropoietin test is used for the diagnosis of chronic renal diseases. EPO is used to see if the kidneys are still producing enough erythropoietin or not. Testing can help the doctor to decide about erythropoietin replacement therapy. If the erythropoietin level is low

erythropoietin replacement therapy increases red cell synthesis in the bone marrow.

Anaemia, Polycythaemia, Bone Marrow Disorders, Kidney failure, Tumours of the kidney

The Erythropoietin Test measures the level of hormone erythropoietin in the blood sample.

The doctor recommends this test when an individual complains of the following conditions.

• Anaemia that does not appear to be caused by iron deficiency, vitamin B12 insufficiency
• Anaemia does not appear due to shortened lifespan of red blood cells (RBCs; haemolysis) or heavy bleeding
• When the RBC count, haemoglobin and haematocrit are all low
• When reticulocyte count is abnormally low
• In those who have chronic kidney illness
• When a complete blood count reveals an increased number of RBCs as well as a high hematocrit and haemoglobin
• When a doctor suspects you have a bone marrow problem like myeloproliferative neoplasms (MPNs) or myelodysplastic syndrome

Erythropoietin Test results are advised by the doctor to

• To determine the difference between primary and secondary polycythaemia
• To differentiate between appropriate secondary polycythaemia and inappropriate secondary polycythaemia
• In candidates for erythropoietin (EPO) replacement therapy.
• In those with chronic renal failure
• In patients who are receiving EPO replacement therapy and have a poor haematopoietic response

The Erythropoietin Test procedure is advised in those with elevated EPO symptoms like:

• Itching
• Dizziness
• Joint pain
• Fatigue
• Breathlessness
• Tenderness in the palms of the hands or soles of the feet
• Sleep disturbance

The Erythropoietin Test procedure is advised in those with depleted EPO symptoms:

• Fatigue
• Shortness of breath
• Increased heart rate
• Dizziness
• Weakness
• Lightheadedness while changing positions
• Headaches
• Pale skin

So those who are suffering from the above symptoms and diseases should check for erythropoietin values. The erythropoietin test results might show abnormal levels in people living in high altitudes and in athletes.

The frequency of Erythropoietin Test depends upon the doctor's advice and on the underlying disease. The erythropoietin test reports are repeated after three months of treatment to monitor the prognosis.

Erythropoietin Test results are repeated 3-4 months in bone marrow disorders to assure healing. The test reports are repeated annually in people with kidney diseases and blood disorders to keep track of health. Erythropoietin Test reports don't need repetition if EPO values were within the normal range.

Before the Test

It is essential to refrain from eating or drinking for a duration of A to B hours before the Erythropoietin Test. This fasting is vital for ensuring the accuracy of the results. Consequently, it is advisable to consult with a healthcare professional prior to any test to ascertain if there are any particular guidelines to be followed.

During the Test

A blood sample will be drawn from a vein in your arm. The procedure includes:

• Cleansing the area where the needle will be inserted with an antiseptic solution.
• Applying a tourniquet around your arm to enhance the visibility of the veins.
• Inserting a sterile needle into the vein to draw the blood, which may result in slight discomfort and will take only a few seconds.
• Transferring the collected sample into a small container or test tube labelled with your test details.

After the Test

Once the blood sample is collected:

• A bandage will be placed over the site of the needle insertion to minimise any bleeding.
• It is common to experience mild soreness or lightheadedness, which should not be a cause for alarm. You may be instructed to rest for a brief period.
• Should you notice any bleeding, discomfort, or rashes at the site of the puncture, please reach out to your healthcare provider.

The Erythropoietin Test values give an idea about the:

• Decrease in the level of erythropoietin in the blood
• Increase in the erythropoietin levels in the blood

The normal range of erythropoietin levels is:

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

Increased or decreased levels of erythropoietin are responsible for various blood disorders.

• Decreased values in Erythropoietin results with anaemia indicate renal dysfunction.
• Increased values in Erythropoietin test results with anaemia indicate bone marrow dysfunction.
• Increased erythropoietin levels with anaemia could be due to iron or vitamin deficiency.
• Increased Erythropoietin test chart values with an increase in RBCs indicates kidneys producing too much erythropoietin.
• Erythropoietin within normal range with an increase in red blood cells indicate primary polycythaemia.

Decreased level of erythropoietin :

• Chronic kidney failure - In chronic renal failure, kidneys can't produce enough EPO. The red blood cell count will diminish and anaemia will occur if your EPO levels are low. Anaemia affects the majority of persons with kidney illness. Anaemia can develop early in renal diseases and worsen as the kidneys fail to produce EPO.  

Increased erythropoietin levels indicative of:

• Polycythaemia - Polycythemia vera is a form of blood cancer. It causes the bone marrow to produce an excessive amount of red blood cells. These extra cells thicken the blood, delaying its flow and increasing the risk of blood clots. In polycythemia vera and congenital/familial primary polycythemias, EPO levels are usually low to low-normal. In secondary physiologic or non-physiologic polycythemias, EPO levels are usually normal or elevated.

• Kidney tumourb - According to one study, renal cell carcinoma cells create an inactive form of EPO, this could explain why renal cell carcinoma patients have high EPO levels.
• Abuse in athletes - Some athletes abuse the blood system to improve their athletic performance. The athletes boost their red cell count to enhance their performance. This is harmful as it can lead to fatal complications.

Some other diseases where erythropoietin values are low are

• Rheumatoid arthritis
• AIDS
• Cancer
• Ulcerative colitis
• Sickle cell disease
• Premature neonates.

Erythropoietin Test results alone cannot discriminate between primary and secondary polycythaemia. In some patients with primary polycythaemia, erythropoietin result chart values are within the normal range. Erythropoietin values in the test report may be higher in people who live at high altitudes than in people who live at lower altitudes.