Introduction to the Blood Screen
Status: S2LectNotes Time: 2025-03-09 Tags: lecturenotes Links: Anaemia Blood
tasks
- blood case 1
- blood case 2
- blood case 3
Objectives:
Take home:
Things to note:
Rambles:
The Blood Count
laboratory assessment of blood cells associated measures
- Haemoglobin level and counts
- HG conc
- red cells count size contents
- leukocytes: count
- platelets
- blood film examination
- to check morphology
What cells look like?
morphology of cells in a normal blood film red cells almost inverse drops on a surface leukocytes have large purple nuclei platelets have central purple granules
Haematopoiesis
Haematopoiesis
split between lymphoid and myeloid lineages
location of haemopoiesis
- adult mostly axial skeleton
- child all bones
- fetus liver and spleen
Principles of regulations
- haematopoiesis
- self renewal of pluripotent stemcell
- differentiation too though
- cytokine signals control this eg(erythropoein thrombopoetin)
- haemotopoises is also supported by marrow stromal cells they now automate haematology analysis
useful measures of blood count
only Hb MCV and RBC is measured everything else can be gathered through math onb these
- haemoglobin (Hb) (g/L) primary o2 carrying measure
- mean cell volume (MCV) (fL)
- mean cell Hb (MCH) (pg)
- reticulocyte count (important)
- haematocrit (not super important) (L/L)
- red bloof cell count (RBC)
- mean cell hb conc (g/L)
compare the patients to a reference interval
anaemia
defined by low haemoglobin g/L for
- age
- male <130g/L
- female <120g/L
- sex
- pregnancy
morphological patterns
- microcytic
- normocytic
- macrocytic
- hypochromic normochromic and hyperchromic roughly correspond to cytic measure and is less useful
Common causes
- microcytic anaemias
- iron deficiecy
- normocytic anaemias
- haemodilution
- renal failure (low epo)
- bone marrow failure
- anaemia of inflammation
- and many others
- Macrocytic anaemias
- folic acid and Vit b12 anaemias (megaloblastic anaemia)
- liver disease
- pancytopenia
- all cell levels down
regulatory dsignals in haemtopoiesis Haematopoietic stem cells • SCF
Multipotential progenitor cells • IL-3, G-CSF, GM-CSF , IL-6, TPO
Act on committed progenitor cells
- used clinically
- G-CSF - neutrophils
- EPO - red cells
- TPO – platelets
- IL-5 - eosinophils
Abbreviations SCF: stem cell factor IL-3: interleukin 3 G-CSF: granulocyte colony stimulating factor GM-CSF: granulocyte-macrophage colony stimulating factor IL-6: interleukin 6 TPO: thrombopoietin EPO: erythropoietin
erythropoiesis proerythroblast erythroblast (nucleated) division iron uptake Hb and reject its nucleus reticulocyte clears RNA mitochondria golgi etc RBC
macrophages hold iron