Erythropoietin Hormone Level (EP)

Sample

1. Take the venous blood.
2. Separate the serum as early as possible.
3. The serum is stable at room temperature.

Purpose of the test (Indications)

1. This test helps to diagnose the cause of anemia.
2. This test also helps to differentiate primary from secondary polycythemia.
3. It detects the recurrence of EP-producing tumors.
4. This can be an indicator for the therapy of EP in patients with renal failure.

Precautions

1. Pregnancy is associated with the raised level.
2. Steroids and birth control pills can increase the level.
3. Blood transfusion gives reduced EP level.
4. Drugs like ACTH, contraceptive pills, and steroids.

Pathophysiology

1. Erythropoietin (EP) is a glycoprotein hormone that regulates erythropoiesis.
   1. This is a glycosylated polypeptide of 165 amino acids with a molecular weight of 34 kDa (31,000 daltons, another source says 45kD).
   2. It has a plasma half-life of  6 to 9 hours.
2. EP is produced in:
   1. 90% produced in the peritubular interstitial cells in the inner cortex of the kidneys.
   2. 10% produced in the liver.
3. EP is the stimulus for the bone marrow to increase RBCs cell numbers.
   1. The increased RBCs number increases the oxygenation in the kidneys.
   2. So stimulus for the EP is reduced.
      1. This feedback mechanism is very sensitive to the oxygen level.

4. There is no store of EP in the body.
5. The stimulus for the activation of the above cells is decreased oxygen, the stimulus for Increased EP production.
   1. There is a feedback mechanism that increased oxygen reduces EP production.

6. EP is inversely related to red blood cell volume and hematocrit.
7. EP is given in the following conditions:
   1. Anemia in the case of chemotherapy patients.
   2. Athlete abuse this hormone to improve the oxygen-carrying capacity and the improvement for the performance.
8. EP is elevated in patients with:
   1. Low hemoglobin due to bone marrow failure due to  Iron deficiency anemia.
      1. Or low Hb due to increased destruction of RBCs in case of hemolytic anemia.
   2. Defective cardiac or pulmonary function.
   3. Damage to renal circulation affects O2 delivery to the kidney.
   4. EP is high in EP producing tumors, like renal cell carcinoma and adrenal gland carcinoma.
   5. Increased EP level in patients with polycythemia is due to decreased O2 (hypoxemia).
9. Low EP level was seen in:
   1. Patient with renal diseases or nephrectomy (bilateral) has low EP level.
   2. Decreased EP level is seen in a patient with Malignant polycythemia vera.
10. Erythropoietin role in renal failure:
    1. EP as recombinant human erythropoietin is very effective in the treatment of anemia due to chronic renal failure, in patients who are on dialysis.
11. Polycythemia has elevated EP level.
    1. While malignant polycythemia vera has reduced EP level.

Normal

Source 1

• Serum = 5 to 36 mU/L
  • To convert into SI units x 1.0 = U/L

Source 2

• 5 to 35 IU/L.

Increased level of EP seen in:

1. Iron deficiency anemia.
2. Megaloblastic anemia.
3. hemolytic anemia.
4. Myelodysplasia.
5. Chemotherapy.
6. Pregnancy.
7. secondary polycythemia due to high altitude and COPD.
8. AIDs.
9. Renal cell carcinoma.
10. Pheochromocytoma.
11. Adrenal carcinoma.

The markedly increased level of EP seen in:

1. Erythropoietin-producing tumors:
   1. Renal adenocarcinoma.
   2. Renal Cyst.
   3. Renal transplant rejection.
   4. Pheochromocytomas.
   5. Polycystic kidney disease.
   6. Sometimes seen in the ovary, adrenal, testicular, breast, and liver carcinoma.

Decreased EP level is seen in:

1. The autoimmune disease like rheumatoid arthritis.
2. Multiple myelomas.
3. Malignancies.

Markedly decreased EP level seen in:

1. Polycythemia Vera (primary).
2. Autoimmune nephropathy.
3. Renal failure and renal diseases.
4. After bone marrow transplantation.

Indication for EP therapy:

1. The best drug for treating anemia due to renal diseases.
2. This can be given in end-stage kidney disease.
3. Anemia of chronic diseases like rheumatoid arthritis or malignancies.
4. It is given I/V or subcutaneously 3 to 7 times per week.
   1. Or once every 1 to 2 weeks depending upon the indication of the patient.
5. The complication of EP are:
   1. Increased blood pressure.
   2. Local site injection.
   3. Increased platelets count.

 

---