Anemias: Phenomenon of LE cell, its differentiation from tart cell. Definition and classification, Laboratory diagnosis of Iron deficiency anaemia, Megaloblastic anaemia, Haemolytic anaemias including sickle cell anaemia thalassaemia, and Aplastic anaemia. 

Phenomenon of LE cell, its differentiation from tart cell.

Anaemia

A decrease in the number of red blood cells or a decrease in the amount of haemoglobin in red blood cells is called anaemia.

Classification of Anaemia

Anaemia can be classified on the following four bases

• 1. Morphological Classification

  • · Microlytic anaemia: Anaemia with a decrease in the size of red blood cells.

  • · Normocytic anaemia: Anaemia with normal size of red blood cells

  • · Macrocytic anaemia: Increase in size of red blood cells. It may be due to a deficiency of vitamin B12 or folate.

• 2. Etiological Classification

  • · Nutritional anaemia: Anaemia due to deficiency of essential nutrients such as iron, folate etc.

  • · Hemolytic anaemia: Anaemia due to the destruction of red blood cells by any reason. It may be due to the immune system or genetic disorder/

  • · Aplastic anaemia: Anaemia due to failure of bone marrow to produce a sufficient number of red blood cells.

  • · Anaemia in chronic diseases: Anaemia is associated with chronic diseases such as rheumatoid arthritis or chronic kidney disease.

• 3. Pathophysiological Classification

  • · Hypoproliferative anaemia: Anaemia due to a decrease in the synthesis of red blood cells in bone marrow.

  • · Hemorrhagic anaemia: Anaemia due to acute or chronic blood loss.

  • · Hemolytic anaemia: Anaemia due to destruction of red blood cells.

  • · Inherited anaemia: Anaemia due to hereditary disease or genetic abnormalities. Examples are sickle cell anaemia or thalassemia.

• 4. Clinical Classification

  • · Acute anaemia: Anaemia develops rapidly due to sudden blood loss or hemolysis.

  • · Chronic anaemia: Anaemia develop slowly and associated with any chronic disease or nutrition deficiency.

Laboratory Diagnosis of Iron Deficiency Anaemia

Iron deficiency anaemia is diagnosed by an assessment of iron present in the body. The following tests are carried out to assess iron status inside the human body

• 1. Complete blood count (CBC): CBC provides the status of blood cells in the whole blood. Low levels of haemoglobin, reduced hematocrit, presence of microcytic red blood cells and hypochromic red blood cells indicate iron deficiency anaemia.

• 2. Serum iron: iron in blood circulation is measured by measuring serum iron. A low level of serum iron indicates iron deficiency anaemia.

• 3. Total iron binding capacity: It measures the maximum amount of iron that can bind to transferrin. Transferrin is a protein that transports iron in the blood. Increased level of free transferring in blood indicates low availability of iron in blood.

• 4. Serum ferritin: Ferritin is an intracellular protein to stores iron. Low serum ferritin level indicates iron deficiency anaemia.

Laboratory Diagnosis of Megaloblastic Anaemia

The following tests are performed to diagnose megaloblastic anaemia

• 1. Complete Blood Count (CBC): The complete blood count provides information about the status of the whole blood. Macrocytic red blood cells with an increase in mean corpuscular volume (MCV) indicate megaloblastic anaemia. Haemoglobin levels and hematocrit levels also decrease in megaloblastic anaemia.

• 2. Peripheral Blood Smear: Observe red blood cells in peripheral blood smear under a microscope. The presence of large oval-shaped red blood cells and hypersegmented neutrophils indicate megaloblastic anaemia.

• 3. Serum vitamin B-12 level and Folate levels: Deficiency of vitamin B12 and folate develop megaloblastic anaemia.

• 4. Homocysteine and Methylmalonic acid level: Vitamin B12 deficiency increases the Homocysteine and Methylmalonic acid level. Increased level of Homocysteine and Methylmalonic acid level indicates megaloblastic acaemia.

• 5. Intrinsic factor antibody and parietal cell antibody: Autoimmune condition develops pernicious anaemia. Vitamin B12 deficiency also occurs in pernicious anaemia. Antibody test positive results will indicate pernicious anaemia. not megaloblastic anaemia.

Laboratory Diagnosis of Haemolytic Anaemia

• The following tests are performed to diagnose haemolytic anaemia.

• 1. Complete blood count (CBC): The complete blood count provides information about the status of the whole blood. A decrease in haemoglobin level, reduced hematocrit and increased reticulocyte count indicates haemolytic anaemia.

• 2. Peripheral Blood Smear: Observe red blood cells in peripheral blood smear under a microscope. The presence of large small round-shaped red blood cells indicates haemolytic anaemia.

• 3. Direct Coombs test (Direct Antiglobulin test): It detects antibodies on red blood cells' surface. These antibodies kill red blood cells to develop autoimmune haemolytic anaemia.

• 4. Indirect Coombs test (Indirect antiglobulin test): The indirect Coombs test detects antibodies in blood plasma. These antibodies destroy red blood cells.

• 5. Serum Bilirubin: The elevated level of bilirubin in the blood indicates an increase in RBC breakdown. Hemolytic anaemia causes the accumulation of bilirubin in the blood.

• 6. Hepatoglobin: Hepatoglobin is a protein in blood. Free haemoglobin enters blood from dead RBCs. Hepatoglobin binds with free globin and remains in the blood. Hepatoglobin level increases in blood in haemolytic anaemia.

• 7. Lactodehydrogenase (LDH): LDH is an enzyme present in RBCs and also in other tissues. The presence of LDH in blood indicates haemolytic anaemia.

Laboratory Diagnosis of Aplastic Anaemia

The following tests are used to diagnose aplastic anaemia.

• 1. Complete Blood Count (CBC): Low level of RBCs, WBCs and platelets in CBC indicates aplastic anaemia.

• 2. Peripheral Blood Smear: A peripheral blood smear shows a reduced number of RBCs, WBCs and platelets under a microscope. The remaining RBCs, WBCs and platelets in peripheral blood smear will have normal morphology. This indicates aplastic anaemia.

• 3. Reticulocyte count: Reduced reticulocytes are reported in aplastic anaemia.

• 4. Bone marrow aspiration and biopsy: Bone marrow examination under a microscope showing a reduced number of hematopoietic cells and an increase in the amount of fat indicates aplastic anaemia.

• 5. Flow cytometry: The flow cytometry technique uses antibodies to identify and characterise blood cells in the bone marrow.

Dr Pramila Singh