Lab Skills

Question 1

How would you separate a blood sample to work out packed cell volume?

Answer 1

Invert blood sample 5-7 times
Hold at 45 degree angle
Place capillary tube in until 3/4 full
Plug the bottom end with plasticine 
Wipe the outside of the capillary tube
Repeat to get another tube
Balance in centrifuge
Spin at 12000 rpm for 5 mins

Question 2

Why do you invert a blood sample and not shake it?

Answer 2

You will destroy the cells

Question 3

Why do you need to plug a capillary tube with plasticine?

Answer 3

So blood is not lost during the centrifuge

Question 4

When a blood sample is centrifuged, it separates into 3 layers. What are these layers?

Answer 4

Plasma
Buffy coat (WBCs and platelets)
Red blood cells

Question 5

What do you use to measure packed cell volume?

Answer 5

Haematocrit table

Aline top of plasticine to top of plasma and read off

Question 6

What would you do if both capillary tubes gave varying packed cell volumes?

Answer 6

Remix the blood and repeat until consistent

Question 7

How would you carry out a test for total plasma protein?

Answer 7

Calibrate refractometer with distilled water to 0 or W
Snap capillary tube above buffy coat
Insert needle into tube containing plasma
Use syringe to expel a drop of plasma onto the refractometer
Close lid and look into the centre of the room (to get light)

Question 8

How do you create a blood smear? (Ignore staining process)

Answer 8

Mix blood sample by inverting
Use capillary tube to drop small amount on end of slide
Use another slide to draw back until touches blood drop
Smoothly push along to the opposite end (to the very end)
Leave to dry

Question 9

How do you stain a blood smear?

Answer 9

Once dry, dip in solutions AB 5 X 1 second
Blot with tissue to reduce cross contamination
Rinse with distilled water on the BACK of the slide
Leave to air dry

Question 10

What are the parts to the bullet shaped blood smear?

Answer 10

Head
Body
Tail (feathered edge)

Question 11

What is the zone of morphology/ monolayer?

Answer 11

Area between body and tail

One cell thick

Question 12

What is the name for the size of an RBC?

Answer 12

Anisocytosis

Question 13

What is the name for the shape of the RBCs?

Answer 13

Poikilocytosis

Question 14

What is the name for the colours of the RBCs?

Answer 14

Polychromasia

Question 15

When examining a blood smear at 100X magnification, what do you need to place on the slide?

Answer 15

Oil

Lower microscope until touches the slide

Question 16

What pattern should be used to move through zone of morphology/monolayer? What should you do?

Answer 16

Battlement pattern

Count 100 cells. Record each type of WBC

Question 17

What 3 things should you observe during urinalsysis?

Answer 17

Colour
Turbidity (haziness)
Smell

Question 18

How would you perform a specific gravity test on urine?

Answer 18

Calibrate refractometer
Place drop onto slide
Read from refractometer

Question 19

How would you do a dipstick analysis for urine?

Answer 19

Draw up 1ml in a 2ml syringe
Put dipstick on paper towel
Drop in each part of dipstick (top to bottom)
Check against bottle for time needed and colours

Question 20

Why are dipsticks not very effective for use in animals?

Answer 20

Designed for humans
Specific gravity inaccurate - use refractometer
Leucocytes inaccurate - do sediment analysis

Question 21

How do you carry out microscopic sediment urinalysis?

Answer 21

Invert sample 5-7 times
Place 1ml in 2 Eppendorf centrifuge tubes
Balance centrifuge and spin at 1500 for 10 minutes
Pour off supernatant
Leave some in to form suspension
Tap to mix
Place onto microscope slide and place cover slip on

Question 22

What should you look for under the microscope for sediment urinalysis?

Answer 22

Blood cells
Other cells
Infectious agents
Crystals