coprology (done) Flashcards
define coprology
(1 mark)
study of faeces
define diarrhoea
(1 mark)
excessive + frequent evacuation of watery faeces
define constipation
(1 mark)
difficult, incomplete / infrequent bowel movements
define steatorrhoea
(1 mark)
excessive fat in faeces
define melena
(1 mark)
dark stool containing blood from upper GI tract
define colitis
(1 mark)
inflammation of the colon
define haematochezia
(1 mark)
stool containing red blood (from lower GIT)
define faceal occult blood
(1 mark)
hidden blood in the stool sample
define meconium
(2 marks)
first faeces from neonate; dark, tar-like + can be green in apperance
reasons to perform a faecal exam?
(9 marks)
- D++
- suspected endo-parasite infestation
- suspected digestion impairment / metabolic disorder
- melenea (dark faeces) / haematochezia (red blood in faeces)
- suspected bacterial infection
- abdo pain
- constipation
- weight loss
- protect general public + veterinary staff from zoonotic diseases
patient prep to obtain a sample?
(3 marks)
no protocol
* dogs walked on lead / in confined area
* cats kept indoors until sample achieved
when is faecal endoparasite exam carried out?
(1 mark)
obtain sample prior to administration of endo-parasites
colection of sample?
(directly from the ground / cat litter)
(6 marks)
- collect immediately
- disinfect area in advance to prevent contamination
- if not disinfected collect top portion of sample only
- any delay in sample collection may result in parasite eggs hatching + crawl away
- cat little, grass, soil / bacteria may contaminate sample
- use of sterile katkor is advised for cat sampling
collection of sample?
(directly from rectum)
(7 marks)
- fresh, uncontaminated sample obtained
- can be carried out on a concious patient
- use appropriate restraint to protect personnel from injury
- faeces may be collected using a gloves finger inserted through the anal spincter into the rectum + scooped back out
- only portion of faeces sampled
- take care not to damage rectal mucosa
- transfer sample into appropriate receptacle
storage and preservation of sample?
(5 marks)
- containers should be sterile + airtight
- sufficent faeces (2-5g) to fill the container
- too much air space encourages parasite eggs to hatch prior to examination
- label the container clearly
- store in fridge max 7 days
after collection, how soon should it be examined?
(4 marks)
exam within 2hrs of collection
OR
store at a max 4 degrees C to prevent further development of parasitic stages
- bacteria examination should be carried out immediately to prevent overgrowth of non-fastidious bacteria
- if exam delayed, dilution with equal partds of 10% formaline, stops endoparasite development
causes of sample deterioriation / inaccurate results
(8 marks)
- general operator error
- incorrect sample collection technique
- delay between evacuation + examination
- incorrect test methods / materials used
- contamination of sample (on collection, in storage / in the lab)
- incorrect patient prep
- incorrect handling, storage / sample preservation
- inappropriate package / storage for transport to external lab
what to look for when visually examinating sample?
(13 marks)
- colour - affected by diet malabsorption / parasitic infestation
- consistency - D++, constipation
- odour - affected by diet, malabsorption / parasitic infestation
- presence of mucous - indicate digestive tract disorder, parasitic infestation
- presence of parasites - intact segmented worms, ascarids (spaghetti strands), tapeworm segments (grains of rice)
- presence of foreign objects - grass, string, bone fragmenents, undigested food, hair
- prescence of blood
prescence of blood in sample
(colour + cause)
(18 marks)
- dark brown / black (melaena) - large quanty of red meat in diet. upper GI haemorhhage e.g. stomach / small intestine
- pink - hepatic dysfunction i.e. biliary obstruction
- red / frank blood - lower GI haemorrhage. enteritis / parasitosis
- white (steatorrhoea) - high fat diet. bones fed within diet. metabolic deficiency e.g. EPI
- blue / green - suspect metaldehyde poisoning
- yellow - increased bile pigment may indicate liver disorder
- mucous - ? lower GIT disorder e.g. IBD, digestive disorder / parasitosis
ways to visualise sample under microscope?
(8 marks)
- direct smear - ‘crude’ analysis technique, that may give an indication of segmented worms, sample size is generally too small to provide validity to findings
- lugol’s iodine stain - detects prescence of starch + muscle fibres in faeces
- trypsin digest test - detects prescence of faecal tryspin
- sudan III stain - detects prescence of fat in faeces
what is the alternative to the other tests when viewing under microscope?
(1 mark)
trysin-like immunoreactivity test
what is trypsin?
(1 mark)
enzyme involved in digestion of proteins
what does the trysin-like immnunoreactivity test show?
(3 marks)
healthy animals have small amount of trypsinogen (secreted by pancreas) in blood circulation
blood sample can detect trypsin-like immunoreactivity
used for diagnosis of exocrine pancreatic insufficiency
what are the ways passive floatation + centrifugation is done?
(egg count)
(9 marks)
- faecal egg count - use modified McMasters method, allows visualisation + identification of worm eggs
- faecal floatation - identification of worm eggs
- baermann technique - detection of faecal larvae
what is faecal occult blood test?
(1 mark)
detects for bleeding in GIT
how is faecal occult blood test done?
(4 marks)
- used to identify prescence of haemoglobin in the sample
- often uses ELISA technology
- false positives can be common due to haemoglobin in meat based diets
- kits are often not sensitive to a low level instinal haemorehage
use of faecal floatation?
(4 marks)
faecal floatation
faecalyser test
modifies mcmaster slides
baermann technique
use of faecal floatation?
(4 marks)
- used in LA + SA faecal analysis
- llows assessment of parasitic ova using faecal floatation
- modified McMasters slide commonly used to aid counting of ova
- floatation of the ova relies on the SG of the ova being less than that of the floatation solution
use of faecalyser test?
(5 marks)
- ‘in house’ commercial product for faecal floatation
- sample collected directly into the pot
- pot contains filter to seperate the liquid + solid portions of the sample
- saturated salt / sugar solution is added to sample within the pot
- sample is then collected from top of the liquid portion with cover slip + examined
what are the 2 types of McMaster slide?
(2 marks)
- single chamber with one chamber + gridded cover slip
- two chambers with a grid etched on the upper surface
calculation of modified McMasters method?
(2 marks)
single counting chamber = no. eggs counted x 50
doubloe counting chamber - (no. eggs counted in first chamber + second) x 50
what are the issues with faecal egg counts?
(8 marks)
- relies on user accuracy
- idenitifying faeces from an individual in herd situation?
- only provides snapshot of egg burden
- immature parasites do not lay eggs but individual could still have high burden of worms
- contamination of sample (collection, in storage, in lab)
- small proportion of total faeces is tested
- incorrect handling, storage / sample preservation might mean that eggs have hatched
- does not accurately establish tapeworm burden / encysted stages of worms
use of baermann technique?
(2 marks)
- used to seperate parasite larvae from faecal sample via sedimentation, using baermann apparatus
- commonly used for detection of Aelurostrongylus abstrusus (in cats) + strongyloides stercoralis (in dogs)
which faecal examinations can be carried out using the ELISA methodolgy snap tests?
(2 marks)
- canine parvo virus antigen test - detects parvo antigens
- canine giardia profile - detect faecal ova + parasites hookworm, roundworm, whipworm + giardia antigens
(they detect surface protein antigen shed in faeces of infected dogs)
standard operating procedures of snap tests?
(9 marks)
- results must be read within 8 mins of the snap being activated to avoid inaccurate results - use of timer
- samples + test kits must be warmed to room temp prior to testing (approx. 30 mins)
- test performed on canine faecal matter only
- test kits must be stored between 2-25 degrees C
- kits are one use, therefore use seperate swab + SNAP device for each patient sample
- do not use kits past expiration date
- do not mix components / conjugates from different kits
- ensure kit is placed on horizontal / flat + secure surface when in use
- do not use SNAP device that has already been activated
disposal of sample?
(3 marks)
- non-hazardous, offensive waste as long as sample has come from animal that is not diseased caused by micro-organism + there is no risk of potential cross-infection
- faeces can contain potentially harmful pathogens, therefore all equipment should be correctly disinfected
- wash hands throughly + remove all PPE prior to leaving laboratory
