Interpreting Full Blood Count and Blood Film

Question 1

What is the normal range for Reticulocyte Count?

Answer 1

A normal reticulocyte count is:

0.5-2%

Reticulocytes are immature red blood cells. There number can be increased as an appropriate response to anaemia, or as part of inappropriate haemopoietic activity (e.g. polycythaemia vera).

Question 2

Red Blood Cell Irregularities

Size

Define the following:

1. Anisocytosis
2. Macrocytosis
3. Microcytosis

Answer 2

Red Blood Cell Irregularities

• Size*
  1. Anisocytosis - abnormal variation in size of RBCs.
  2. Macrocytosis - large RBCs that may be due to vitamin B12 of folate deficiency; also seen in pernicious anaemia, liver disease, hypothyroidism, some bone marrow diseases, and pregnancy.
  3. Microcytosis - small RBCs that may be due to iron deficiency anaemia, long-stnading inflammation due to infections or conditions such as rheumatoid arthritis, or inherited disoders such as thalassaemia.

Reference: Lab Tests Online

Question 3

Red Blood Cell Irregularities

Shape

Define the following:

1. Poikilocytosis
2. Acanthocytes
3. Echinocytes
4. Elliptocytes
5. Keratocytes
6. Rouleaux
7. Sickle Cells
8. Target Cells
9. Teardrop Cells
10. Schistocytes
11. Spherocytosis

Answer 3

Red Blood Cell Irregularities

• Shape*
  1. Poikilocytosis - variation in the shape of an RBC and may include several different abnormalities at the same time
  2. Acanthocytes - spur/thorn/spiculated cells; irregular shaped cells with 5-10 spicules; may be present in liver or thyroid conditions, or in post-splenectomy patients
  3. Echinocytes - burr/crenated/berry cells; may have 10-30 spiny projections; often seen in patients with renal failure or malnutrition; may be artefact
  4. Elliptocytes - elliptical-shaped RBS seen in hereditary elliptocytosis and various anaemias
  5. Keratocytes - horn cell; a half-moon or spindle-shaped RBC that may be seen in DIC or in patients wiht a vascular prosthesis
  6. Rouleaux - RBCs that appear as a stack of coins; seen in patients with inflammatory illnesses, anaemia, multiple myeloma or macroglobulinaemia
  7. Sickle Cells - crescent-shaped RBCs characteristic of Sickle Cell Anaemia
  8. Target Cells - leptocytes/codocytes; RBCs that resemble a bullseye; commonly seen in patients with liver disease, iron deficiency, haemoglobinopathies, or thalassaemia
  9. Teardrop Cells - dacrocytes; RBCs that resemble a long teardrop; often seen in myelofibrosis
  10. Schistocytes - fragments or broken pieces of RBCs; may be due to a disorder that is causing RBCs to be very fragile, or due to mechanical haemolysis as sometimes seen in patients with artificial heart valves or HUS
  11. Spherocytosis - sphere-shaped RBCs found in hereditary spherocytosis, or in autoimmune haemolytic anaemia (associated with ‘warm’ antibody, IgG-mediated reaction; see Nelson p. 2329 and PasTest p.312-313.)

Reference: Lab Tests Online

Question 4

Red Blood Cell Irregularities

Colour

Define the following:

1. Hypochromasia
2. Polychromasia

Answer 4

Red Blood Cell Irregularities

• Colour*
  1. Hypochromasia - may be seen in a variety of disorders including thalassaemia and iron deficiency; the RBC is pale in colour due to insufficient haemoglobin and contains a large, hollow middle (central pallor)
  2. Polychromasia - blue-staining RBCs indicating that they are immature due to early release from the bone marrow

Reference: Lab Tests Online

Question 5

Red Blood Cell Irregularities

Structure

Define the following:

1. Nucleated RBCs
2. Reticulocytes
3. Siderocyte/Sideroblast/Ringed Sideroblast
4. Basophilic Stippling
5. Heinz Bodies
6. Howell-Jolly Bodies
7. Cabot’s Rings

Answer 5

Red Blood Cell Irregularities

• Structure*
  1. Nucleated RBCs - normoblasts; very immature form of RBCs seen when there is a severe demand for RBCs to be released by the bone marrow; may be seen in abrupt blood loss, severe anaemia, myelofibrosis, thalassaemia, miliary TB, and cancers involving the bone marrow; can be normal in infants for a short time after birth.
  2. Reticulocytes - immature RBCs that are usually polychromatic in colour; a few are normal in the circulation; elevated numbers may be seen in acute blood loss, hypoxia, and haemolysis (e.g. G6PD, Sickle Cell Disease, Autoimmune Haemolytic Anaemia)
  3. Siderocyte/Sideroblast/Ringed Sideroblast - when RBCs are stained with Prussian blue dye, iron granules may be seen; ring sideroblasts may be seen in some forms of hereditary anaemia and in myelodysplastic syndrome
  4. Basophilic Stippling - dark blue dots inside the RBC; due to the precipitation of nuclear material (ribosomes) and may be due to heavy metal poisoning (e.g. lead), nutritional deficiencies, or myelofibrosis
  5. Heinz Bodies - large inclusion bodies (granule) in the RBCs when stained with crystal viole; may be due to an enzyme (G6PD) deficiency, unstable haemoglobin variant, thalassaemia, and autoimmune haemolytic anaemia
  6. Howell-Jolly Bodies - small round remnants of nuclear DNA inside the cell; present in Sickle Cell Anaemia, haemolytic anaemia, or megaloblastic anaemia; may be seen post-splenectomy.
  7. Cabot’s Rings - threadlike inclusions that form a ring within the RBC; may be seen in a variety of anaemias.

Reference: Lab Tests Online