Faecal Collection & Analysis

Question 1

How should sample be collected from rectum

Answer 1

Clean around anus

Use lube to prevent damage to mucosa

Question 2

Yellow faeces may indicate (2)

Answer 2

Malassimilation/malabsorption

Hepatic disease

Question 3

Faecal smear used to detect… (3)

Answer 3

Worm eggs
Protozoan oocysts
Partially/undigested food

Question 4

Principle of faecal flotation technique

Answer 4

Faces in salt/sugar solution separates
- heavy debris sinks
- light eggs float
Centrifuge can be used to assist
- 1000-1,500rpm for 3-5mins

Question 5

What does modified McMaster determine

Answer 5

Number of eggs per gram

Question 6

Brief description of modified McMaster

Answer 6

Faeces (3G) mixed w/water (42ml), sieved
Filtrate centrifuged, supernatant discarded
Sediment resuspended with saturated salt solution
- made up to 15ml
Pipettes into chambers
Number of eggs/g = total count x 50

Question 7

In what cases would occult blood be found (3)

Answer 7

Chronic haemorrhage

• ulcers
• neoplasia
• parasitism

Question 8

How is occult blood tested for

Answer 8

Animal on meat free diet for 3 days

Chemical reaction used to determine presence (colour change)

Question 9

Faecal flotation technique steps

Answer 9

Mix faeces and water, sieve
Let filtrate stand for 5mins
Remove supernatant, add flotation solution - fill to top so meniscus present
Place cover slip on top, leave 10-20 mins
Place on slide
Scan at low power