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.
Which two conditions can polycythaemia rubra vera transform into?
1 - Myelofibrosis.
2 - Acute myeloid leukaemia.
List 2 treatments of polycythaemia rubra vera.
1 - Venesection (bloodletting).
2 - Hydroxycarbamide.
List 5 cells that are included in a white cell differential count.
Granulocytes (polymorphonuclear cells):
1 - Neutrophils.
2 - Eosinophils.
3 - Basophils.
Mononuclear cells:
4 - Lymphocytes.
5 - Monocytes.
What is the primary function of neutrophils?
Phagocytosis.
What is the primary function of eosinophils?
Destruction of large pathogens (e.g. parasites) by release of granules containing major basic protein (MBP).
List 2 functions of basophils.
1 - Immediate hypersensitivity through IgE binding, histamine release and leukotriene release.
2 - Modulation of the inflammatory response.
List the 3 types of lymphocyte.
1 - T cells.
2 - B cells.
3 - NK cells.
List the two types of T cells.
1 - CD4+ cells (helper cells).
2 - CD8+ cells (cytotoxic cells).
List 3 functions of T cells.
1 - Regulation of B cells.
2 - Destruction of virus, fungi and infected cells.
3 - Delayed hypersensitivity.
List 2 functions of B cells.
1 - To produce antibodies.
2 - To present antigens.
List 2 functions of NK cells.
1 - Lysis of antibody-coated cells.
2 - Destruction of tumours and virus-infected cells (without antibodies).
List 2 functions of monocytes.
1 - Phagocytosis.
2 - To present antigens.
List 4 causes of neutrophilia.
1 - Reactive (infective or non-infective).
2 - Tissue infarction.
3 - Demargination (movement of cells away from the margins of a blood vessel).
4 - Malignancies.
List 7 causes of neutropenia.
1 - Ethnic neutropenia.
2 - Congenital neutropenia.
3 - Cyclical neutropenia (cycles of recurrent neutropenia).
4 - Reactive (especially viral).
5 - Bone marrow infiltration.
6 - B12 / B9 (folate) deficiency.
7 - Drugs.
Define epitope.
The part of an antigen molecule to which an antibody attaches itself.
What are the two types of expansion?
- Polyclonal (many precursor cells usually in response to multiple antigens).
- Clonal (one precursor cell).
What is the most common lymphoproliferative disorder?
Chronic lymphocytic leukaemia.
Give an example of risk factor for lymphoproliferative disorders.
Increasing age.
List the symptoms of lymphoproliferative disorders.
Trick question!!! Often asymptomatic, requiring observation only.
How are lymphoproliferative disorders controlled (if necessary)?
Chemotherapy.
List 4 causes of lymphocytosis.
1 - Smoking.
2 - Splenectomy.
3 - Infection.
4 - Lymphoproliferative disorders.
List 4 causes of lymphopenia.
1 - Reactive.
2 - Drugs.
3 - Congenital immunodeficiency.
4 - HIV.
List 2 causes of monocytosis.
1 - Infection (especially EBV).
2 - Leukaemia.
List 2 causes of monocytopenia.
1 - Marrow infiltration.
2 - Genetic defects in maturation (e.g. GATA2 transcription factor).
List 3 causes of basophilia.
1 - Myeloproliferative disorders.
2 - Infection.
3 - Hypothyroidism.
List 3 causes of basopenia.
1 - Steroids.
2 - Anaphylaxis.
3 - Hyperthyroidism.
List 4 causes of eosinophilia.
1 - Parasitic infections.
2 - Atopy (predisposition towards allergic hypersensitivity reactions).
3 - Hypereosinophilic syndromes.
4 - Drugs.
List 2 causes of eosinopenia.
1 - Alcohol.
2 - Steroids.
What is the name of the precursor cells to platelets?
Megakaryocytes.
Define thrombocytosis.
A condition where platelets are abnormally high.
List 5 causes of thrombocytosis.
1 - Reaction (to an infection, inflammation or infarction).
2 - Splenectomy.
3 - Iron deficiency.
4 - Bleeding.
5 - Myeloproliferative disorders such as essential thrombocythemia.
Which mutation is associated with essential thrombocythemia?
JAK2.
List 9 causes of thrombopenia.
1 - Immune thrombocytopenic purpura.
2 - Thrombotic thrombocytopenic purpura.
3 - Disseminated intravascular coagulation.
4 - HELLP (haemolysis (H), elevated liver enzymes (EL) and low platelet count (LP)).
5 - Splenomegaly.
6 - Alcohol / liver disease.
7 - Bone marrow infiltration.
8 - Familial thrombocytopenias.
9 - von Willebrands disease.
List 4 treatments of immune thrombocytopenic purpura.
1 - Steroids.
2 - Splenectomy.
3 - Rituximab.
4 - Azathioprine.
What is the function of antiplatelet drugs?
To prevent clot formation.
- They DON’T change platelet count.
