Parasitology manual for

chemists of branches

By Yosra Hussein ( Training specialist ) 1

 Routine Stool Analysis
 Test Principle :
1. Naked Eye Examination .
2. Microscopic Examination .

 Clinical Significance :
For detection of parasitic infection .

By Yosra Hussein ( Training specialist ) 2

 Precautions Before Analysis
‫يفضل احضار العينه في المعمل و في حالة تعذر ذلك يتم احضار‬ .1
‫العينه للمعمل خالل نصف ساعه و يتم فحصها خالل ساعه خاصة‬
‫ و ذلك‬Loose or Watery or Mucoid samples ‫في حالة‬
: ‫ألن‬
Entamoeba histolytica trophozoites

Rabidly disintegrate
at room temp.
Giardia lamblia trohozoites

By Yosra Hussein ( Training specialist ) 3

 ‫‪Precautions Before Analysis‬‬

‫‪ .2‬رفض العينات المختلطه بالبول ‪.‬‬

‫‪ .3‬رفض العينات التي يتم احضارها في علبه كرتون أو حفاضه في حالة‬
‫األطفال ‪ ،‬لذلك يتم قلب الحفاضه علي الجانت البالستيك و ارتداء‬
‫الطفل لكيس تجميع بول علي فتحة البول لتجنب اختالط البول بالبراز و‬
‫نقل العينه مباشرة في الكوب المخصص لذلك ‪.‬‬
‫‪ .4‬ال يؤخذ ملينات ‪.‬‬

‫) ‪By Yosra Hussein ( Training specialist‬‬ ‫‪4‬‬

 Steps Of Analysis
 Naked Eye Examination for :
1. Colour of stool sample

Brown Light brown Greenish Reddish Black Clay

or or
Yellowish Dark brown

Normal Undigested Much green Mucoid Occult blood Obstruction

fat vegetables samples or of
eaten or due tinged drugs bile ducts
Giardia or with
H. nana infection blood By Yosra Hussein ( Training specialist ) 5
 Steps Of Analysis
2. Odour :
Normally Fecal but in case of parasitic infection it
becomes Offensive.

3. Consistency :
Loose ; Watery or Mucoid samples should be examined
by Direct smear method ( Iodine stained 10% in
distilled water ) .

Formed ; Semi-formed ; Soft samples should be examined

after concentration by sedimentation method .
By Yosra Hussein ( Training specialist ) 6
 Steps Of sedimentation method
1. Put 7 ml. of Formal saline 10% in a centrifuge tube .
2. Place a tea-spoon stool sample & emulsify it .
3. Filter the mixture in another tube .
4. Add 1 – 2 ml. of ethyl acetate solution to dissolve fat & do vortex .
5. Centrifugation for 10 min. at 3000 rpm .
6. Remove the fat layer ( debris ) on the surface by wooden stick .
7. Discard the supernatant & put 30 µl. of the
sediment on glass slide + 20 µl. of Iodine 10% in distilled water
to detect protozoa cysts & trophozoites .

By Yosra Hussein ( Training specialist ) 7

 Steps Of Analysis
4. Mucus : ( Write : Nil ; + ; ++ ; +++ )
 In case of loose or watery stool sample with mucus tinged
with blood ; it is an indication of infection with
Entamoeba histolytica trophozoites

 Presence of mucus accompanied of the formed stool sample

may be due to constipation or irritable colon .

5. Blood : ( Write : Nil ; + ; ++ ; +++ )

May be due to piles or anal fissure .

By Yosra Hussein ( Training specialist ) 8

 Steps Of Analysis
6. Reaction ( PH ) :
Normally it is alkaline .
Assess PH of diarrheic stool specimen using litmus
paper It turns acidic in some conditions :
Ex : Entamoeba histolytica trophozoite infection .
This helps to differentiate amoebic dysentery from bacillary
dysentery .

7. Undigested food :
( Write : Nil ; + ; ++ ; +++ )

By Yosra Hussein ( Training specialist ) 9

 Steps Of Analysis
8. Worms :

Enterobius vermicularis Ascaris lumbricoids Taenia saginata

By Yosra Hussein ( Training specialist ) 10

 Steps Of Analysis
 Microscopic Examination :
(Using low power ( 10x ) for screening)
1. Vegetable cells : Write : Nil ; Few ; Some : Many

2. Starch : Write : Nil ; Few ; Some ; Many

By Yosra Hussein ( Training specialist ) 11

 Steps Of Analysis
3. Muscle fibers : Write : Nil ; Few : some ; Many

4. Fat globules : write : Nil ; Few ; Some : Many

By Yosra Hussein ( Training specialist ) 12

 Steps Of Analysis
5. Protozoa ( Cyst ) : Write : Nil ; Few ; Some ; Many

E. histolytica/dispar E. Coli Giardia lamblia

( 1-4 nuclei ) ( 5-8 nuclei ) ( 4 nuclei with axonemes )

( 1 – 4 nuclei )

By Yosra Hussein ( Training specialist ) 13

 Steps Of Analysis
6. Protozoa ( Trophozoite ) : Write : Nil ; Few ; Some ; Many

E. histolytica Giardia lamblia

By Yosra Hussein ( Training specialist ) 14

 Steps Of Analysis
7. Helimenths

Ova ( Eggs of worms ) Larvae

Large Medium Small Strongyloids stercoralis
( 250 µ )

By Yosra Hussein ( Training specialist ) 15

 Steps Of Analysis
Ova ( Eggs of worms ) :
The eggs size according to use the low power (10x)

Large Medium Small

Schistosoma mansoni Hymenolepis nana Enterobius
Fasciola Ascaris Taenia
Ancylostoma Trichuris
Capillaria
Heterophyes

By Yosra Hussein ( Training specialist ) 16

 Steps Of Analysis
 Ova ( Eggs ) :
1. Large size eggs :
Schistosoma mansoni egg Fasciola egg

By Yosra Hussein ( Training specialist ) 17

 Steps Of Analysis
2. Medium size eggs :
Hymenolepis nana egg Ascaris egg

Ancylostoma egg ( Hook worm )

By Yosra Hussein ( Training specialist ) 18

 Steps Of Analysis
3. Small size eggs :
Enterobius Egg Taenia egg Trichuris egg

Capillaria egg Heterophyes egg

By Yosra Hussein ( Training specialist ) 19

 Steps Of Analysis
8. Pus cells 9. RBCs
Normal range ( 0 – 5 / H.P.F. )

10. Yeast cells ( Write : Nil ; few ; Some ; Many )

By Yosra Hussein ( Training specialist ) 20

 Steps Of Analysis
11. Other :
Blastocystis hominis

Written in the following conditions

Watery sample No parasites Many blastocystis

causing diarrhea are present

By Yosra Hussein ( Training specialist ) 21

 Artifacts mistaken with eggs in stool
samples
Ascaris egg :
Pollen grains ( by 40x lens )

Vegetable cells

By Yosra Hussein ( Training specialist ) 22

 Artifacts mistaken with eggs in stool
samples
Ancylostoma egg : H. nana egg :
Mite eggs in house dust

Capillaria egg :
Fungal spore Pollen grain
Strongyloids larva :
Hairs of variable length

By Yosra Hussein ( Training specialist ) 23

 Giardia cyst & Yeast cells in stool

Giardia cyst

Yeast cells

By Yosra Hussein ( Training specialist ) 24

 After Analysis
 If pus cells is more than 10 / H.P.F. or with clumps
; PH is alkaline & no parasite can be seen during
examination : Recommend for stool culture .
 For watery stool samples showing no parasites :
Recommend test for cryptosporidium in stool for adults .
( Spread thin sheet of patient’s stool on a glass slide &
stain by Modified Ziehl Neelsen ( MZN ) stain by using ( 100 X ).

By Yosra Hussein ( Training specialist ) 25

 After Analysis
 Recommend test for cryptosporidium & Rota virus in stool in
children less than 5 years with watery samples & presence of
no parasites .
 Recommend for peri - anal swab test for Enterobius egg :
( Swab is done in the morning before going to the toilet ;
using transparent cello tape & one slide only is required )
Females worm migrates by night to pass
out of the anus

By Yosra Hussein ( Training specialist ) 26

 After Analysis
 Please don’t write many bacteria in stool
analysis report as there is always normal
bacterial flora passing down in normal stool;
samples .

By Yosra Hussein ( Training specialist ) 27