Lab (blood/faecal/urine testing) Flashcards
Why may we do faecal testing?
- Presence of pathogenic bacteria/virus
- Presence of parasites
- Cause of underlying disease
- Digestive function
What are the possible collection methods for faecal testing and what may their limitations be?
- Ground
- Don’t know when voided/age
- High risk of contamination from environment - Rectal
- Consider animal compliance
What is the difference between plasma and serum?
PLASMA:
- Liquid using anti-coagulant (eg EDTA/Lithium heparin)
- Plasma contains fibrinogen
- Plasma has higher levels of protein and globulins
SERUM:
- Liquid left over after clotted
- More commonly chemistry testing
- Potassium and phosphate higher levels
- Allow to clot for 10-15 minutes before spinning
Discuss 5 reasons to take a blood sample
Any 5 from:
- Pre and post operative bloods to check if protocol safe for patient (liver and kidney function)
- Check hydration (PCV)
- Check after ingesting toxins for toxic dose
- Hormone testing (eg hyperthyroid)
- Internal haemorrhaging (eg RTA)
- Wellness testing to find baseline
- Drug use (competition animals) and drug reviews (long term NSAIDs)
What equipment do you need for a free flow urine collection?
- COllection pot
- Sample pot
- Gloves
- Non-absorbable litter (feline) eg Katkor
What equipment is needed to collect a manual expression urine sample?
- Kidney dish
- Restraint aids
- Sample pot
What equipment is needed for catheterisation urine collection?
- Catheter
- Syringe
- Collection pot
- Sample pot
- Gloves
- Lubrication
- Pen
- Speculum for females
What equipment is needed for a cystocentesis urine collection?
- Needle
- Syringe
- Clippers (dependent on patient)
- Ultrasound
- Sample pot
- Pen
What are the advantages and disadvantages of tape impressions?
ADVANTAGES:
- Quick
- Cheap
- Non-invasive
DISADVANTAGES:
- Only for dry lesions
- Only takes superficial sample
- Can be fiddly
What are the advantages and disadvantages of direct impression/impression smears?
ADVANTAGES:
- Can use on lesions, tissues or exudate
- Identify gram positive/negative
- Quick
- Direct contact with sample
DISADVANTAGES:
-Can’t get into crevices/pockets of skin
What are the advantages and disadvantages of hair brushing?
ADVANTAGES:
- Quick
- Easy
- Cheap
DISADVANTAGES:
- Difficult on double coat animals
- Only get superficial analysis
What are the advantages and disadvantages of hair pluck?
ADVANTAGES:
- Simple method
- Can identify burrowing mite & fungi
- Help identify Cushings & hyperthyroid
What are the advantages and disadvantages of skin scrapes?
ADVANTAGES:
- Gain cells, exudate and parasites
- Can gain superficial or deep analysis
- Get more information/results
DISADVANTAGES:
- Need to remove excess hair
- Consider immune depressant animals (secondary infection)
- May cause more trauma
What are the advantages and disadvantages of swabs?
ADVANTAGES:
- Can take from direct wound/tissue
- Identify skin folds
DISADVANTAGES:
- Must take care not to damage ear canal for aural swabs
- Ideally tested before treatment started
What is the difference between haematology and biochemistry testing?
Haematology identifies various components of blood
Biochemistry is an analysis of the blood plasma or serum to evaluate organ function
What are the 3 components of Diff-Quik?
- Methanol (light blue)
- Eosin (red)
- Methylene (purple)
What colour tubes would the following anticoagulants be found in?:
- EDTA
- Lithium heparin
- Potassium oxalate
- Sodium citrate
- Plain/Serum
- Acid-Citrate dextose
- Red/pink
- Green (with gel)
- Yellow
- Purple
- White/Brown (with gel)
- Yellow
What colours could be seen in urine and would what these indicate?
Transparent & Yellow: -Normal but intensity may indicate concentration Brown/Yellow: -Bile pigment present (shock, renal issues, dehydration) Red/Brown: -RBC present (?) -Oestrus, stale sample Bright Red: -Urinary tract trauma -Inflammation -Cystitis Brown/Black -Azoturia (contains products of muscle cell destruction -Excess exercise
What do you assess macroscopically with a urine sample
- Amount
- Colour
- Turbidity
- Smell/odour
What are the 4 methods for collecting a urine sample?
- Free flow
- Manual expression
- Catheterisation
- Cystocentesis
When is the best time to collect a urine sample and why?
First thing in the morning as it will be more concentrated and more likely to find abnormalities
How must a urine sample bee stored after collecting and why?
In a preservative such as Boric acid to stabilise the pH and prevent the breakdown of ammonia and CO2
It must also be kept in a fridge to prevent crystallisation occurring and altering results
Why does care need to be taken when manually expressing a bladder?
Check animal is not blocked and therefore applying too much pressure causing the bladder to rupture
What are the normal PCV readings for:
- Cats
- Dogs
- Equine
- 24-45%
- 37-55%
- 30-49%
What needs to be taken into consideration when reading PCV?
Each animal is individual and would need base line reading for accurate interpretation (eg. Greyhounds generally have higher reading to normal)
What can the refractometer be used to measure?
- Specific gravity of urine
- Total protein (g/DL)
- Fibrinogen
- Colostrum
What equipment is required for the Baermann Technique?
- Funnel
- Stand
- Plastic tubing
- Microscope
- Clamp
- Cheese cloth
- Pipette
- Microscope slide and cover slip
- Strainer
- Scissors
- Petri dish
- Iodine
Explain how to carry out the Baermann technique
- Use 5-10g of faeces
- Fill tubing and funnel with Luke warm water and sit faeces in for 24 hours
- Take couple of mls from the bottom and either leave to sit for a few minutes or centrifuge at 1000 rpm
- Remove supernatent and then remove sediment from Petri dish, put on a microscope slide with iodine and cover with cover slip
- Use 10 X 10 lens to examine under the microscope
Identify the equipment required for the McMaster technique
- Beakers
- Saturated salt solution
- Measuring cylinder
- Sieve
- Scales and stirrer
- Double-chambered microscope slide
For the McMaster technique, identify the dilutions of solutions and the ratios for testing
- Salt solution = 400g sodium chloride : 1 litre water
2. 4g faeces sample : 56ml salt solution
For the McMaster technique, identify the key points for results
- Take sample from middle of faecal sample
- Leave to stand for 5 minutes for egg to rise
- Use 10 X 10 lens on microscope
For the McMaster technique, identify the calculation used
Count eggs seen in both chambers and multiply by 50, giving you eggs/gram (anything up to 200 = normal)
What are the possible faecal sample testing methods and their limitations?
Pooled sample (collected over a couple of days and mixed together):
- Not ideal for looking at bacteria
- Samples should not be stored in the fridge between collections
- Is a cheaper option
Non-pooled sample (collected over a couple of days in separate collection pots):
- More accurate
- Needs to be consecutive
Identify the common faecal analysis tests and what they are used for
- Baermann technique - Live larvae in faeces
2. McMaster technique - Worm egg count
Identify the types of microscopes and their properties
- Compound:
- Most common
- Uses binoculars
- Multiple lenses inside - Stereo/dissecting scope:
- Less magnification
- Used for dissecting (histology)
- Can move around specimen and look in 3D - Digital:
- Similar to compound
- Can record and upload to USB
- Useful to produce guidance
- Save and send images
- More specialist
What are some rules for care and cleaning microscopes?
- Support when lifting (not by the arm)
- Never push or pull along a surface
- Light should not be left on too long
- Clean using disinfectant
- Use lint-free tissue to not damage lens
What are the 3 types of centrifuge?
- Fixed-Angle head
- Swing-out head
- Microhaematocrit
What speeds and times need to be set for: 1. Urine 2. Blood 3. Serum In a centrifuge?
- 2000 rpm for 5 minutes
- 10,000 rpm for 5 minutes
- 2,500 rpm for 10-15 minutes (let clot for 15-20 minutes before spinning)
