The Full Blood Count Flashcards
Briefly describe the method used to count cells of the blood.
Flow cytometry:
1 - The blood is passed through a thin stream.
2 - A laser is shone through the stream, which scatters.
3 - The side scatter and forward scatter are measured.
4 - Side scatter measures complexity (presence of granules and nuclei), and forward scatter measures volume.
List 10 values measured in the full blood count.
Where possible, indicate how each value can be calculated.
1 - Haemoglobin concentration.
2 - Haematocrit.
3 - Packed cell volume.
4 - Red blood count.
5 - Mean cell volume (PCV / RBC).
6 - Mean cell haemoglobin (Hb / RBC).
7 - Mean cell haemoglobin concentration (Hb / PCV).
8 - Reticulocyte count.
9 - White blood cell differential count.
10 - Platelet count.
Define anisocytosis.
A condition in which red blood cells are of unequal size.
Define poikilocytosis.
A condition in which red blood cells are abnormally and irregularly shaped.
Define anisopoikilocytosis.
A condition in which red blood cells are both of unequal size (anisocytosis) and are abnormally and irregularly shaped (poikilocytosis).
Define acanthocytes.
A condition in which red blood cells have a spiky appearance.
Define codocyte.
A red blood cell with a bell-shape (AKA target cells).
What might cause an increased number of codocytes?
Liver disease.
Define dacrocyte.
A type of poikilocyte that has a teardrop shape.
Explain why nucleated red blood cells might appear in the blood.
- After infancy, RBCs normally only contain a nucleus during the early stages of the cell’s life, and the nucleus is ejected as a part of cellular differentiation before the cell is released into the bloodstream.
- So if nucleated RBCs are seen on an adult’s peripheral blood smear, it suggests that there is a very high demand for the bone marrow to produce RBCs, and immature RBCs are being released into circulation.
What might cause toxic neutrophils (neutrophils with abnormally large granules) to appear in the blood?
1 - Severe infection or inflammation.
2 - As a result of denatured proteins with rheumatoid arthritis.
Define left shifted neutrophils.
An increase in the number of immature neutrophils in the blood.
What is the term used to describe an excess of cells?
Polycythaemia.
What is the term used to describe a lack of cells?
Anaemia.
What are the two criteria used to classify anaemia?
1 - MCV.
2 - Cause (of decreased production / increased loss).
What is a relative polycythaemia?
Why might a relative polycythaemia arise?
- Relative polycythemia is an apparent rise of the erythrocyte level in the blood; however, the underlying cause is reduced blood plasma.
- Relative polycythemia can be caused by loss of body fluids, such as through burns, dehydration, and stress.
Define primary polycythaemia.
Give an example of a cause of primary polycythaemia.
- Polycythemias due to factors intrinsic to red cell precursors.
- Polycythemia rubra vera (PRV), or erythremia, occurs when excess red blood cells are produced as a result of a myeloproliferative disorder of the bone marrow.
Define secondary polycythaemia.
Polycythaemia caused by an increase in erythropoietin production.
What is the difference between appropriate and inappropriate secondary polycythemias?
Appropriate secondary polycythaemias arise due to appropriate / normal response of the kidneys to produce erythropoietin, whereas inappropriate secondary polycythaemias arise due to innappropriate / abnormal response of the kidneys to produce erythropoietin.
Give an example of a cause of secondary appropriate polycythaemia.
High altitude.
Give an example of a cause of secondary inappropriate polycythaemia.
Renal / liver tumours.
List 4 signs and symptoms of polycythaemia rubra vera.
1 - Plethoric (red) face.
2 - Aquagenic pruritis.
3 - Splenomegaly.
4 - Basophilia.
Which mutation is associated with polycythaemia rubra vera?
JAK2 mutation.