2 - EXAMINATION OF FECAL SPECIMENS Flashcards
Contains bacteria, cellulose, and other undigested foodstuffs, GI secretions, bile pigments, cells and electrolytes, and water
Feces
Around ?g of stool is passed per day
100-200g
- Most common method of diagnosis in parasites (protozoans and metazoans)
- Best collected in clean, wide-mouthed containers made of waxed cardboard or plastic with tight-fitting lid to ensure retention of moisture and prevent spillage
Examination of Fecal Specimens
Parasite Stages Detected
Cyst
Trophozoites
Oocyts
Eggs
Larvae
Adult worm
Clearance period following ingestion of certain drugs and compounds:
Oily materials, non-absorbable antidiarrheal preparations, barium, bismuth, or antimalarial agents
7 days
Clearance period following ingestion of certain drugs and compounds:
Antimicrobial agents
2-3 weeks
Clearance period following ingestion of certain drugs and compounds:
Gallbladder dyes
3 weeks
amount of stool
Formed
2-5 grams
amount of stool
Watery
5-6 tablespoons
Liquid specimen should be examined within ? after passage
30 minutes
Soft specimen should be examined within ? after passage
1 hour
Formed specimen should be examined within ? with refrigeration after passage
24 hours
Order of processing:
Bloody/Mucoid
Watery
Formed
Color
Brown
Dark brown
Light brown
Consistency
Formed
Soft
Loose
Watery
Check for the following:
- mucus
- blood
- larval or adult worms
- proglottids
Most easily performed parasitologic test
Direct Wet Mount / Direct Fecal Smear
DFS is most useful when fresh specimens, especially liquid stools or duodenal aspirates, are examined for
motile trophozoites or helminth larvae
DFS is for screening or diagnosis?
Screening test only
Small amount of stool is mixed with a drop of ? and ? and covered with a coverslip
0.85% saline, Lugol’s iodine
may be used in the event that a protozoan trophozoite is found
Buffered Methylene Blue
Wait for ? before examining to allow the stain to penetrate the trophozoite for about ?
5-10 minutes, 30 minutes
If parasite ova or larvae are seen, report as:
Positive for species and stage of the parasite
Ex: Positive for Ascaris lumbricoides egg
If parasite ova or larvae are NOT seen, report as:
No Intestinal Parasite Seen (NIPS)
saline smear findings
Huge no. of:
Eggs
Protozoan trophozoite motility (Amoebas, flagellates)
iodine smear findings
Huge no. of:
Cyst morphological details
