Lab Flashcards
How much of the body does blood make up?
7-10% of bodyweight
What is blood made up of?
A fluid part - plasma
A solid part - Erythrocytes, Leucocytes and Thrombocytes
What materials are needed for collecting a blood sample?
Needle - 19-23G, 3/4inch, depends on patient size
Syringe - 1-5ml, sterile and tested plunger
Sample Tubes - labelled with patient details
Swab soaked in chlorhexidine solution
Clean dry swab and bandage material
Gloves
Clippers - clean and tested, various sizes
Assistant/ restrainer
Potentially a tourniquet
Where are the blood collection points in dogs, cats and rabbits?
Jugular, cephalic, lateral saphenous
*in rabbits also have marginal ear vein
What size needle is used for parenteral injection?
21-26
What are things you should not do when collecting blood that can damage/clot blood?
Do not draw back forcefully on plunger - can collapse the vein and damage blood
Always transfer to collecting tube ASAP - to prevent contamination and clotting
Always expel the blood gently into the tube and remove the needle prior to doing this - to avoid cell damage
Always collect enough blood to fill to the required level on the collection tube
What is serum?
The fluid compartment of blood that clotting factors have been removed from i.e. no solid
What would you collect serum in?
A brown plain tube, or a clear serum gel tube WITHOUT anticoagulant
What is different about serum samples?
The blood is allowed to clot. In brown tubes it will clot at room temp after about 2 hours. In serum gel tube, use centrifuge to spin down and the gel forms a layer between the serum and the blood.
How can serum be stored? Short and long term?
In fridge for a few days between 2-8 degrees. Or in freezer lower than -20. Both will need to be brought up to room temp and gently mixed before testing
What do sample tubes for unclotted samples contain?
Anticoagulant
How can plasma be stored?
Short term in fridge for a few days at 2-8 degrees
Long term in freezer at less than -20 degrees
What is a pink tube? What is it used for?
Ethylene Diamine Tetra-acetic Acid (EDTA)
Minimal change in morphology of blood cells
Used in blood smears and cell counts
don’t use for reptiles or avian species
What is an orange tube? What is it used for?
Lithium Heparin
Salts in the tube bind with and prevent clots
Used for biochemical tests and hormone tests
What is a yellow tube? What is it used for?
Sodium Fluoride or Potassium Oxalate
Must be used for blood glucose as it stops the oxidation of glucose
What is Haemolysis?
Rupture of RBCs causing haemoglobin to be released staining the plasma or serum red/pink
What causes Haemolysis?
Cell trauma due to vigorous agitation Extremely rapid collection Adding to a hypotonic solution Leaving plasma unseparated in transit Needle too fine Didn't remove needle when decanting blood
What would cause a sample to clot?
If there is insufficient anticoagulant for the volume of blood
Too long to take or test sample
What is Lipaemia?
Fat globules in serum or plasma
Appears cloudy
What causes lipaemia?
Recently fed Liver disease (hyperlipidaemia - fats not metabolised)
What is and what causes an icteric sample?
High levels of bilirubin
Indicates liver disease
normal for horses and cattle
What is a haematology test?
A total Blood Cell Count
What makes up a haematology test?
- Quantitative
- PCV, Total white cell count etc.. - Qualitative
- Blood smear examination for changes in cell shape and structure