L05-The full blood count Flashcards
How does the full blood count analyser assess which cells are in the blood?
It shines a laser through the cells and measures the scatter of the light, this allows the size and granularity of the cells to be measured and hence the cell type to be determined.
What is MCHC, how is it calculated and what does it show?
MCHC is the mean cell haemoglobin concentration. It is calculated by the Hb/haematocrit. Low MCHC is shown in microcytic anaemias and is high in hereditary spherocytosis, sickle cell and red cell agglutination.
What does nucleated red blood cells show?
They show reticulocytes mainly or other immature red cells in the blood. High levels of these imply an attempt to raise red blood cell levels in response to a haemolysis
What is packed cell volume?
A measurement derived from centrifugation similar to haematocrit.
What is polycythaemia?
An increased viscosity of the blood due to an increased haematocrit, this can be due to genetic disorder or environmental e.g. training at altitude
In adults what are the most common type of lymphocyte?
Neutrophils
What is neutrophilia and what is it most commonly associated with?
It is a high neutrophil count and is most commonly associated with bacterial infection
What is neutropenia and what is it most commonly associated with?
A low neutrophil count that is associated with decreased production or increased destruction of neutrophils. A fever in a patient with neutropenia is a medical emergency as they cannot fight it without neutrophils.
What are patients with neutropenia often given to stimulate more neutrophils to be produced?
G-CSF
What are the 4 main factors that influence lymphocyte count?
Production - production of lymphocytes in the bone marrow is controlled by growth factors
Antigen driven proliferation - expansion of lymphocytes in order to provide an adaptive response to infection
Sequestration - sequestered into the bone marrow of lymph nodes rather than the blood
Apoptosis - extent to which the lymphocytes are being apoptosed
What does lymphocytosis mean?
An increase in the number of lymphocytes in the blood
What does lymphopenia mean?
A decrease in the number of lymphocytes in the blood
What are the main causes of lymphopenia?
Most commonly it is iatrogenic (due to medication)
Sometimes can be inherited with the worst kind as severe combined immunodeficiency (SCID)
Also seen in a number of viral infections e.g. HIV
What is thrombocytopenia and what are the main causes?
Low platelet count (less than 150cells/cm cubed) Mains causes are: -Underproduction of platelets -Increased destruction -Sequestration
What are common causes of platelet underproduction?
Problems with the bone marrow that prevent megakaryocyte production e.g. infection, drugs, vitamin B12 deficiency
May have problems with thrombopoietin
