FBC Flashcards
What can a FBC detect?
Hb conc Haematocrit Red cell count Mean cell volume Mean cell Hb Mean cell Hb conc Reticulocyte count WBC differential Platelet count
What is haematocrit?
Also known as packed cell volume - The proportion of blood taken up by RBC
What is red cell count used for?
Used in microcytic anaemias
What is mean cell volume?
Shows the size of RBCs, used to determine the type of anaemia.
PCV / RBC count
What is MCH?
Hb / RBC count
What is MCHC?
Hb / PCV
What is WBC differential?
Sum of the leukocytes and immature precursors.
Neutrophils should be greater than lymphocytes in adults but the opposite in children.
What is a blood film?
Shows if the FBC is accurate, clumping, shapes of RBC, Hb content and presence of blasts
What is hypochromic?
Pale, low Hb content
What is EDTA Ig?
EDTA collates Ca in the blood to prevent clotting. The Ig causes clumping in a test tube but is asymptomatic in the body.
What does a low Hb conc mean?
<13g.dL males or <11.5g.dL = ANAEMIA
<130g.L, <115g.L
What does a low MCHC show?
Hypochromic = microcytic anaemia
What does a high MCHC show?
Hyperchromic due to spherocytosis and sickle cell
What does a high reticulocyte count show?
Attempt to increase RBC production due to HAEMOLYSIS
What does a high haematocrit and red cell count show?
ABSOLUTE POLYCYTHEMIA >55%
What is polycythemia vera?
A BM disease causing increased production of blood cells. Precursor to acute myeloid leukaemia.
How does polycythemia present?
Splenomegaly, pluritis (itching), plethoric face (red faced)
How is absolute polycythemia treated?
Venosection to remove the blood volume and hydrocycarbiamide
What does the presence of immature leukocytes show?
Sepsis or leukaemia
What does a high neutrophil count show?
Neutrophilia - Pregnancy or corticosteroids
What does a low neutrophil count show?
Neutropenia - reduced production from deficiencies, increased destruction from AI or chemo, sequestration
How is neutropenia treated?
Prophylactic antibiotics and G-CSF to boost neutrophil count
What is demargination?
Neutrophils sit on the vascular endothelium to respond quickly in high numbers. But during a seizure the neutrophils dissociate from the endothelium and the seizure then presents as an infection due to the neutrophilia.
What is lymphocyte count affected by?
Production under GF control
Antigen driven proliferation during infection
Sequestration within lymphoid tissue
Apoptosis through receptor ligation and GF deprivation and phagocytosed by macrophages to prevent intracellular spillage
What does a monoclonal expansion of lymphocytes suggest?
Malignancy in the absence of infection
What may cause lymphocytosis?
Smoking, splenectomy, infection, lymphoproliferative disease
What is Hodgkin’s lymphoma?
Affects B lymphocytes and starts in the lymphatic system
What is Non-Hodgkin’s lymphoma?
Affects both B and T lymphocytes and can start either in the lymphatic or in other organs.
What is leukaemia?
Neoplasm that arises in the marrow and spreads to blood
What may be the cause of lymphopenia?
SCID
What is suggested by an increase in monocytes?
Infection of leukaemia
What is suggested by a decrease in monocytes?
Genetic defect in maturation or BM infiltration
What is suggested by an increase in basophils?
Malignancy, infection, HYPOthyroidism
What is suggested by a decrease in basophils?
HYPERthyroidism, steroids, anaphylaxis
What is suggested by an increase in eosinophils?
Parasitic infection, allergy, drug reaction
What is suggested by a decrease in eosinophils?
Alcohol, steroids
What is thrombocytopenia?
A reduced platelet count of <150cells/cm3 with the increased risk of excessive bleeding
What causes thrombocytopenia?
Underproduction - reduced megakaryocytes levels. Caused by infections, drugs (chemo), vit B12 and folate deficiency, aplastic anaemia
Increased destruction - Increased megakaryocyte levels. Caused by ITP, lupus, DIC, CVID
Sequestration - within the spleen due to cirrhosis, virus or malignancy
What is ITP? How is it treated?
Immune thrombocytopenic purpura. Autoimmune related due to HIV or Hep C.
Treated with steroids, azathiopine and splenectomy to remove autoIg.
What may cause abnormal platelet function and therefore prolonged bleeding time?
Van Willebrand disease detected by PFA-100 test
Aspirin - inhibits cyclo-oxygenase irreversibly for 1 week (needed for thromboxane production)
Iron and folate deficiency