Lab Maintenance and Blood Sampling

Question 1

What is a centrifuge?

Answer 1

equipment which spins a substance to separate fluid from solid content
- using centripetal force

PCVs, Plasma, Urine sediment

Question 2

what are the different types of centrifuges?

Answer 2

fixed-angle head
- most common
- specimen in a fixed position - 25-40 degrees from vertical

swing out head
- specimen starts in the vertical position
- as the rotor turns, the specimen swings out
- returns to vertical position when cycle complete

microhaematocrit
- horizontal slots available for capillary tubes

Question 3

how to ensure safety when using a centrifuge?

Answer 3

do not open whilst still running
always add the plate
make sure samples are balanced
- otherwise spins incorrectly

Question 4

what centrifugal speeds should we use?

Answer 4

blood - 10,000rpm for 5 mins
urine - 2,000rpm for 5 mins
serum - 2,500rpm for 10-15mins
-> let clot for 15-20min prior

Question 5

centrifuge maintenance?

Answer 5

clean regularly
check for broken glass
- impact spin
replace rubber ring regularly
place on flat strong surface

Question 6

normal PCV ranges?

Answer 6

cats - 24-35%
dogs - 35-45%
-> sighthounds 45-55% as athletic

Question 7

reasons for high PCV?

Answer 7

dehydration - less serum than should be
polycythaemia - produce too many RBCs
acute bleeding

Question 8

reasons for low PCV?

Answer 8

anaemia

Question 9

what is a refractometer?

Answer 9

hand-held piece of equipment which measures:
- specific gravity of urine
- total proteins of serum

Question 10

how do you calibrate a refractometer?

Answer 10

Place 2-3 drops of distilled water on the prism
Hold refractometer up to light source and look down eye piece
Calibrate the refractometer to 1.000 on the USG scale
Lift cover and dry prism surface using a dry tissue

Question 11

normal total proteins ranges?

Answer 11

cats - 66-86g/l
dogs - 55-74g/l

Question 12

what are the types of blood tubes?
colour? anticoagulant? test?

Answer 12

red - EDTA - haematology

orange - lithium heparin - biochemistry

yellow - potassium oxalate with sodium fluoride - glucose

purple - sodium citrate - coagulation

white/brown (with gel) - plain - serum

Question 13

where can you collect a blood sample?

Answer 13

cats
- jugular
- medial saphenous
- cephalic

dogs
- jugular
- lateral saphenous
- dorsal pedal
- cephalic
- marginal ear

birds
- jugular
- brachial
- basilic
- medial metatarsal

snakes
- ventral coccygeal
- dorsal coccygeal

Question 14

equipment needed for taking bloods?

Answer 14

prep solution
suitable needle and syringe
relevant blood tubes

Question 15

pros/cons of different needle sizes for blood samples?

Answer 15

large needles (eg green 21G)
- better flow
- minimal pressure needed
- no haemolysis
- increased bleeding risk

small needle (eg blue 23G or orange 25G)
- haemolysis likely
- lower bleeding risk
- higher pressure needed
- slower flow - higher clotting risk

rule of thumb:
- large dogs - green
- small dogs/cats - blue
- exotics - orange

Question 16

what does haematology test for?

Answer 16

the evaluation of blood cells
- a complete blood count

examples:
- RBC count
- WBC count - neutrophils, basophils, eosinophils, lymphocytes, monocytes
- Haemoglobin concentration
- Reticulocyte count
- Total protein
- Platelet count

helps with checking organ functions, infections and bleeding

Question 17

Reasons for changes in RBC count?

Answer 17

High = polycythaemia
- high production

Low = anaemia
- destroys own RBCs
- not making enough RBCs
- bleeding/trauma

Question 18

reasons for changes in WBC count?

Answer 18

High = leukocytosis
- infection/inflammation

Low = leukopenia
- bone marrow not producing enough
- infection - all WBCs working cant keep up production

Question 19

reasons for changes in platelet count?

Answer 19

High = thrombocytosis
- when another disease or condition causes high platelet count
- not common

low = thrombocytopenia
- big problem as blood wont clot
- bleeding so run out of platelets
- body destroying own platelets

Question 20

what does biochemistry test for?

Answer 20

the evaluation of the blood plasma/serum for a wide variety of chemical compounds

examples:
- electrolytes - sodium/potassium
- urea
- creatinine
- calcium
- phosphorus
- amylase
- total proteins - albumin and globulin
- bilirubin

Question 21

Plasma vs Serum?

Answer 21

plasma
- heparin tubes
- anticoagulated blood
- contains clotting factors

serum
- plain tube
- coagulated blood
- doesn’t contain clotting factors

Question 22

what are the electrolytes?
why would you test for their levels?

Answer 22

sodium
potassium
- high causes arrhythmia and bradycardic (blocked cats)
calcium
chloride
- need to watch with lactating bitches - diet? cant feed?
magnesium
phosphate

Question 23

why test for lactate and glucose levels?

Answer 23

lactate
- produced during anaerobic respiration
- if the patient is in hypovolemic shock (eg GDV/cesarean) - less venous return
- so less persuasion to blood to cells
- switches to anaerobic preparation

glucose
- high = diabetes
- low = likely in neonates/toy dogs
-> immature liver so cant break down/produce or store

Question 24

what can we test to assess kidney function?

Answer 24

blood urea nitrogen
- increased = failure

SDMA
- an early marker for kidney failure

Creatinine
- level changes once 70% of the kidney has failed

Question 25

what can we test to assess liver function?

Answer 25

bile acids/bilirubin
- problems with gall bladder or biliary tree

ammonia
- problems with gall bladder

ALT, ALKP, AST, Y-GT
- all enzymes linked to liver
- high amounts = problem

Question 26

what can we test to assess fats in the blood?

Answer 26

triglycerides and cholesterol
- what fats break down into

Question 27

what can we test to assess pancreatic function?

Answer 27

amylase and lipase
(enzymes produced by the pancreas)