Red blood cell parameters Flashcards
How do you collect a capillary blood sample
- Explain to test the donor and gain consent 2. Have them clean their hands with alcohol gel (evaporate), suitable puncture site 3. Puncture using a lancet, use cotton swab to clean the first drop of blood 4. Tender loving care
Intention to treat analysis Vs Per protocol analysis
Intention to treat analysis is important. Drug may work but not everyone wants to take it
What is haematocrit
Volume of red blood cells as a ratio of whole blood volume
How to calculate haematocrit
Centrifuge blood Lay the tube in the reader groove
How to calculate red cell count
Dilute the blood Drop diluted blood onto haemocytometre Put under the light microscope and count
How to calculate haemoglobin
Lower haemocue cuvette into the drop and the centre should fill from yellow to red Cuvette inserted into haemocue device
How to draw blood
Venous Heel prick Finger prick
How to measure WBC, RBC and platelet now
Counted in large automated instruments Electronic impulses generated when cells flow between a light source and a sensor
How to measure haemoglobin
Spectrometer
What is polycythaemia
Too many red cells in circulation Hb, RBC and Hct are all increased
Cause of polycythaemia
Excessive transfusion Increase in erythropoietin e.g, in hypoxia Inappropriately use of erthyropoietin, tumour, doping Abnormal bone marrow - hyperviscosity which can lead to thrombosis, blood can be removed and drugs can be given to reduce bone marrow production
What is anaemia
Reduction in the amount of haemoglobin in a given volume of blood below what would be expected
How is mean cell volume calculated
Hct/RBC
What is the difference between MCH and MCHC
MCH is the absolute amount of haemoglobin in an individual red cell MCHC is the concentration of haemoglobin in a red cell (MCHC is related to the shape)
Why is it important to distinguish between iron deficiency and thalassaemia trait
Important not to prescribe iron supplements that have no effect
Advice on genetic counselling
