Your source for clinical lab test information.

Sample

  1. Make fresh blood smear.
  2. Take blood in EDTA.
  3. Hemolytic anemia is due to RBC hemolysis.

Definition of hemolytic anemia

The causes of RBC hemolysis may be:

  1. Hereditary is due to intrinsic red cells defects.
  2. Acquired are due to environmental changes.
  3. Intravascular hemolysis when the destruction of the RBCs takes place in the blood vessels and hemoglobin is released.
    1. Hemoglobin in the blood gives rise to hemoglobinuria.
  4. Extravascular hemolysis when the destruction of the RBCs takes place in the mononuclear phagocytic system.

Hereditary Causes of hemolytic anemia:

  1. RBC cell membrane defect:
    1. Abnormality in the cell membrane cytoskeleton leads to spherocytosis and elliptocytosis.
    2. Abnormal lipid synthesis like an increase in the membrane lecithin.
  2. Red cell enzyme deficiency:
    1. G-6-PD deficiency.
    2. Pyruvate kinase deficiency.
    3. Hexokinase deficiency
    4. Glutathione synthetase deficiency
  3. Disorders of hemoglobin synthesis:
    1. Hemoglobin synthesis defect like Thalassemia.
    2. Abnormal structure of the hemoglobin-like Sickle cell anemia, Hb E.

Acquired Causes of hemolytic anemia:

  1. Antibody-mediated cytotoxic reaction (Type II) like ABO incompatibility.
    1. Hemolytic autoimmune anemia is seen with cold antibody and warm antibody.
    2. Drug-induced hemolytic anemia seen in Methyldopa, penicillin,
  2. Microangiopathic hemolytic anemia is seen due to the trauma of RBCs in the cardiac prosthetic valve, and fibrin deposition in the microvasculature.
  3. Infections: Hemolytic anemia due to toxins like a malarial parasite, septicemia, Clostridium welchii, pneumococci, staphylococci, and lead poisoning.
    1. Hemolytic anemia due to snake venom and spiders bite.
    2. Hemolytic anemia due to lead poisoning and copper toxicity.
  4. Hemolytic anemia due to extensive burns.
  5. Hemolytic anemia in splenomegaly.
  6. Paroxysmal nocturnal hemoglobinuria.
  7. Anemia due to acquired RBCs membrane abnormality.
  8. Secondary to liver and kidneys diseases.

Clinical presentation of hemolytic anemia:

  1. There is pallor of the mucous membrane which can be judged from the tongue.
  2. There is fluctuating of jaundice. In some patients, bilirubin will very high and may need blood transfusion exchange.
  3. Urine shows no bilirubin but there is the presence of the urobilinogen.
  4. Gallstones are common in these patients.
  5. The patients with sickle cell disease may develop ulcers around the ankle.
  6. Aplastic crises may be seen in these patients.
  7. Rarely folate deficiency causes aplastic crises.

The Hemolytic anemia shows the following lab changes:

  1. Hb is reduced and may be mild to moderate decreased from 6 to 10 G/dl.
  2. Reticulocytes are increased from 5 to 20 % (Reticulocytosis).
  3. MCV is normal or slightly increased,
  4. MCHC is increased.
  5. Bone marrow shows erythroid hyperplasia.
    1. Normal myeloid: erythroid ratio of 2:1 to 12:1 is reduced to 1:1 or much more reduced.
  6. Coombs test direct is negative which differentiate it from autoimmune hemolytic anemia.
  7. Peripheral blood smear shows poikilocytosis and polychromatophilia due to reticulocytes.
    1. There are elliptocytes and fragmented RBCs.
    2. There is normochromic and normocytic anemia picture.
  8. RDW is increased due to anisocytosis and poikilocytosis. Unlike other normochromic and normocytic anemias.
    1. Increased reticulocytes lead to increased MCV but not like megaloblastic anemias. 
  9. Serum bilirubin is raised.
    1. Urine urobilinogen is positive.
    2. Stercobilinogen is increased
  10. Serum haptoglobin is absent.
Parameters Hemolytic anemia
Hb Decreased  6 to 10 g/dL
Reticulocytes Increased 5 to 20%
MCV Normal or mild increase
MCHC Increased
Bone marrow Erythroid hyperplasia
Coombs test Direct is negative
RDW Increased

Possible References Used

Back to tests