Haematology and Anaemia Flashcards
What is a microhaematocrit
Procedure for determining the ratio of the volume of packed RBCs to the volume of whole blood via centrifugation
What would you see from a haematocrit of a patient suffering from dehydartion
Higher percentage of erythrocytes, due to swelling of RBCs
What would you see from a haematocrit from a patient with Bilirubinaemia (or jaundice)
Lower percentage of RBCs and yellow plasma
What would you see from a haematocrit from a patient with haemolysis
a red colour in the plasma
What would you see in the haematocrit of a patient with lipaemia
A grey colour to the plasma
What would you see in the haematocrit of a patient suffering from leucocytosis or thrombocytosis
A larger buffy coat
What is the coulter principle
The Coulter method of sizing and counting particles is based on measurable changes in electrical impedance produced by nonconductive particles suspended in an electrolyte
What are the measured values of RBCs, Mean Corpusuclar volume (MCV), Platelets, WBCs and Haemoglobin?
RBCs=absolute number per litre
MCV=average volume of the RBCs
Platelets&WBCs=Absolute number per litre
Haemoglobin=amount of haemoglobin in blood (g/l)
How is haematocrit calculated
HCT= Mean cell volume x red blood cell count / 100
MCV= average size of RBCs
What is mean corpuscular haemoglobin
Average amount of haemoglobin per RBC, in picograms (pg)
How is MCH calculated
MCH pg= Hb x 10/ RBC count
What is mean corpuscular haemoglobin concentration (MCHC)?
Average concentration of haemoglobin in the cells relative to size/ volume of cell
How is MCHC calculated
MCHC g/dl = Hb x 100/Hct
What are limitations of automated systems when calculating haematocrit, MCH ect
- They will not give reliable differential white cell counts
- Occasionally small RBCs will be undercounted and counted as platelets
- Large platelets may get counted as RBCs
- Can’t ID RBC morphology, WBC Morphology or blood parasites
What are some common problems with blood samples
- correct tube selection
- clotting
- haemolysis
- appropriate tube filling
- lipaemia
- Labelling correctly
Why is microscopic examination of blood smears an essential skill
Differential leucocyte counts
- Erythrocyte and leucocyte morphology
- presence of abnormal cells and parasites
- platelet counts
- low cost
What is the erythrocyte sedimentation rate
It is used to monitor or rule out inflammatory infective conditions. ESR also indicates the extent of inflammation and infection in rheumatic fever.
Larger aggregates sediment more rapidly
What can a total iron binding capacity test tell you
It can be used as an indirect measure of the amount of transferrin in the blood
What is anaemia
Reduced haemoglobin concentration or amount of circulating erythrocytes, meaning a lower oxygen carrying capasity in the blood
What 3 variables can define anaemia
- Total haemoglobin
- PCV or haematocrit
- RBC count
How can chronic renal failure cause anaemia
Due to the reduction in EPO production in the kidneys
What does Macrocytic, Normocytic and Microcytic mean with regards to RBC morphology (MCV) during anaemia?
Macrocytic = increased RBC size Normocytic = RBC size normal Microcytic = decreased RBC size
What does Hypochromic, Normochromic and Hyperchromic mean with reagrds to haemoglobin content (MCHC) during anaemia?
What does Hypochromic, Normochromic and Hyperchromic mean with reagrds to haemoglobin content (MCHC) during anaemia?
Describe the bone marrow response in regards to reticulocyte count during anaemia?
Regenerative = increase in reticulocyte count Non-regenerative = normal - low
Why does an increase in reticulocytes lead to and increase in MCV and a decrese in MCHC?
Reticulocytes are bigger than RBCs
Reticulocytes have less haemoglobin that RBCs
