Introduction to Blood - Anaemia Intro

Question 1

Why is blood used for lab diagonosis?

Answer 1

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)

Question 2

What do we look at when examining peripheral blood?

Answer 2

Blood cells and haemostasis (control of bleeding and clotting)

Question 3

What do we look at for blood cells?

Answer 3

Cell counts (RBCs, leukocytes), blood film examination (cell morphology and confirm cell count), specialized tests

Question 4

Describe the morphology of red cells.

Answer 4

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.

Question 5

Describe the morphology of platelets.

Answer 5

Pale blue cytoplasm, central red stained granules, really small

Question 6

Name leukocytes and reticulocytes.

Answer 6

Neutrophil, eosinophil, basophil, monocyte, lymphocyte, band forms and metamyelocytes
Reticulocytes require a special stain

Question 7

What is the automated haematology analyser used for?

Answer 7

Automated count of cells

Question 8

Describe how the automated haematology analyzer works.

Answer 8

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

Question 9

What does the peripheral examination look at for blood cells?

Answer 9

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)

Question 10

What is the reference range/interval for a population?

Answer 10

The range of values present in 95% of healthy individuals of a specified population, for a given test.

Question 11

What factors influence blood test results for individuals?

Answer 11

Developmental age - fetal/child/adult/old age
Ethnic differences
Gender - male/female
Environmental factors - pregnancy/high altitude/climate

Question 12

What happens to Hb at higher altitudes?

Answer 12

It increases.

Question 13

Which stage of life has the highest Hb?

Answer 13

New born - need lots of Hb to extract oxygen from womb.

Question 14

What is essential information in a blood test?

Answer 14

MCV, Hb, MCH

Question 15

What is anaemia?

Answer 15

Reduced haemoglobin for age, gender and geographic/ethnicity.
Gives clue about oxygen transport in blood

Question 16

Name the descriptions of cell type in anaemia.

Answer 16

Normocytic
Microcytic
Macrocytic

Question 17

Name the descriptions of Hb cell concentration.

Answer 17

Normochromic

Hypochromic

Question 18

Name the common types of anaemia.

Answer 18

Microcytic hypochromic
Normocytic normochromic
Macrocytic normochromic

Question 19

What type of anaemia is iron deficiency?

Answer 19

Microcytic hypochromic anaemia

Question 20

What are some features of hypochromic microcytic anaemia?

Answer 20

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

Question 21

What indicators of the blood test do you look at for anaemia?

Answer 21

Hb

MCV - determine the size of the cells

Question 22

What are some causes for normochromic normocytic anaemias?

Answer 22

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

Question 23

What are the main causes for macrocytic anaemias?

Answer 23

Megaloblastic anaemia (deficiency of vitamins needed for nucleic acid metabolism - folic acid and vit B), delayed and abnormal maturation in marrow. Many other causes.