Introduction to Blood - Anaemia Intro Flashcards
Why is blood used for lab diagonosis?
It is largely homogenous
It is in equilibrium in tissues
It shows reactive responses in disease states (e.g. blood cells, plasma proteins, products from metabolism, leakage from tissue cells)
What do we look at when examining peripheral blood?
Blood cells and haemostasis (control of bleeding and clotting)
What do we look at for blood cells?
Cell counts (RBCs, leukocytes), blood film examination (cell morphology and confirm cell count), specialized tests
Describe the morphology of red cells.
Relatively uniform in size. Up to 1% of red cells may be oval or have a bizarre shape. Central pale zone occupies up to 1/3rd red cell diameter.
Describe the morphology of platelets.
Pale blue cytoplasm, central red stained granules, really small
Name leukocytes and reticulocytes.
Neutrophil, eosinophil, basophil, monocyte, lymphocyte, band forms and metamyelocytes
Reticulocytes require a special stain
What is the automated haematology analyser used for?
Automated count of cells
Describe how the automated haematology analyzer works.
Discrimination of cells based on cell size, cytoplasmic/nuclear complexity, detection of perioxidase enzyme.
Single cells assessed by laser beam - absorption and light scattering.
Cell counts of the order of 10 000 cells to give precision.
Hb concentration measured by colour absorbance
What does the peripheral examination look at for blood cells?
Red cell concentration (RBC) Hb Hct - Hematocrit MCV - mean cell volume MCH - mean cell Hb (MCHC - mean cell Hb concentration = not reported, too much error)
What is the reference range/interval for a population?
The range of values present in 95% of healthy individuals of a specified population, for a given test.
What factors influence blood test results for individuals?
Developmental age - fetal/child/adult/old age
Ethnic differences
Gender - male/female
Environmental factors - pregnancy/high altitude/climate
What happens to Hb at higher altitudes?
It increases.
Which stage of life has the highest Hb?
New born - need lots of Hb to extract oxygen from womb.
What is essential information in a blood test?
MCV, Hb, MCH
What is anaemia?
Reduced haemoglobin for age, gender and geographic/ethnicity.
Gives clue about oxygen transport in blood
Name the descriptions of cell type in anaemia.
Normocytic
Microcytic
Macrocytic
Name the descriptions of Hb cell concentration.
Normochromic
Hypochromic
Name the common types of anaemia.
Microcytic hypochromic
Normocytic normochromic
Macrocytic normochromic
What type of anaemia is iron deficiency?
Microcytic hypochromic anaemia
What are some features of hypochromic microcytic anaemia?
Pencil cells and target cells
Erythroblasts show reduced Hb production and no stainable iron in marrow = no stores.
Can have an early response to treatment of iron deficiency - well filled red cells become present
What indicators of the blood test do you look at for anaemia?
Hb
MCV - determine the size of the cells
What are some causes for normochromic normocytic anaemias?
Haemodilution after acute blood loss
Renal failure
Chronic/persistent infection or inflammation - mechanism is reduced normal red cell production
Usually a secondary feature of an underlying disorder
What are the main causes for macrocytic anaemias?
Megaloblastic anaemia (deficiency of vitamins needed for nucleic acid metabolism - folic acid and vit B), delayed and abnormal maturation in marrow. Many other causes.
