Type of test Blood

 Normal findings

 5-35 IU/L

 Test explanation and related physiology

 EPO is a hormone produced by the kidney. In response to decreased oxygen, the production of EPO is increased. EPO stimulates the bone marrow to increase RBC production. This improves oxygenation in the kidney, and the stimulus for EPO is reduced. This feedback mechanism is very sensitive to minimal persistent changes in oxygen levels. In patients with normal renal function, EPO levels are inversely proportional to the hemoglobin concentration.

As a hormone, EPO is often administered to patients who experience anemia as a result of chemotherapy. Occasionally athletes, in order to improve oxygen-carrying capacity and thereby improve performance, abuse this hormone.

EPO testing is performed to assist in the differential diagnosis of patients with anemia or polycythemia. EPO is elevated in patients who have low hemoglobin due to failure of marrow pro duction or with increased RBC destruction (iron-deficiency or hemolytic anemia, respectively). However, patients with anemia caused by renal diseases (or bilateral nephrectomy) do not have elevated EPO levels. The renal cells are damaged by disease. EPO levels fall and these patients develop anemia.

 Patients who have polycythemia as an appropriate response to chronic hypoxemia have elevated EPO levels. Yet patients who have malignant marrow causes of polycythemia vera may have reduced EPO levels. Some renal cell or adrenal carcinomas can produce elevated EPO levels.

Interfering factors

 • Pregnancy is associated with elevated EPO levels.

• The use of transfused blood decreases EPO levels.

& Drugs that may increase EPO levels include adrenocorticotropin hormone, oral contraceptives, and steroids.

Procedure and patient care

• See inside front cover for Routine Blood Testing.

 • Fasting: no

• Blood tube commonly used: red or gel separator

Abnormal findings

Increased levels

- Iron-deficiency anemia

- Megaloblastic anemia

- Hemolytic anemia

- Myelodysplastic syndrome

- Chemotherapy

- AIDS

-  Pheochromocytoma

- Renal cell carcinoma

- Adrenal carcinoma

Decreased levels

- Polycythemia

- vera Renal diseases

- Renal failure