Diagnostic Techniques

Question 1

Simplest and easiest technique to facilitate detection of intestinal parasites that infected subjects pass in their feces

Answer 1

Direct Fecal Smear (DFS)

Question 2

What are the reagents used for DFS?

Answer 2

Normal Saline Solution (NSS: 0.85%) and Lugol’s Iodine

Question 3

Most common sample for parasitology

Answer 3

Stool

Question 4

Characteristics determined in macroscopic analysis

Answer 4

Color, consistency, mucus & blood presence, adult worms present

Question 5

Routine procedure for microscopic analysis

Answer 5

DFS

Question 6

Most ideal technique for microscopic analysis

Answer 6

Permanent staining

Question 7

Increases the sensitivity especially if the parasite is in low count

Answer 7

Concentration technique

Question 8

How many mg of stool should be put in the glass slide?

Answer 8

2 mg

Question 9

Quantifies the egg can correlate the severity of the disease with the intensity of the infection and can assess the efficacy of treatment

Answer 9

Kato-Katz Technique

Question 10

True or False: Kato-Katz Technique can be used for all parasites

Answer 10

False. This is not applicable to all.

Question 11

What are the primary parasites used in Kato-Katz Technique?

Answer 11

Hookworm
Ascaris lumbricoides
Trichuris trichiuria
*can also be useful for Schistosoma

Question 12

Unit used when conducting Kato-Katz

Answer 12

eggs per gram stool (epg)

Question 13

What is the role of glycerine?

Answer 13

Clearing agent

Question 14

For how long should the cellophane strips be soaked into glycerine before procedure?

Answer 14

24 hours prior to use

Question 15

How long are hookworm eggs visible?

Answer 15

30-60 minutes

Question 16

How long are A. lumbrocoides and T. trichiuria eggs visible?

Answer 16

months

Question 17

How long are schistosome eggs recognizable?

Answer 17

Several months; examination preferred 24 hours within slide preparation

Question 18

What is the amount of stool and epg for template with Diameter: 9 mm
Thickness: 1 mm?

Answer 18

50 mg; count x 20

Question 19

What is the amount of stool and epg for template with Diameter: 6 mm
Thickness: 1.5 mm?

Answer 19

41.7 mg; count x 24

Question 20

What is the amount of stool and epg for template with Diameter: 6.5 mm
Thickness: 0.5 mm?

Answer 20

20 mg; count x 50

Question 21

What are the classifications of intensity of infection in A. lumbricoides?

Answer 21

light: 1-4,999 epg
moderate: 5,000-49,999 epg
heavy: more than or equal to 50,000 epg

Question 22

What are the classifications of intensity of infection in T. trichiuria?

Answer 22

light: 1-999 epg
moderate: 1,000-9,999 epg
heavy: more than or equal to 10,000 epg

Question 23

What are the classifications of intensity of infection in hookworms?

Answer 23

light: 1-1,999 epg
moderate: 2,000-3,999 epg
heavy: more than or equal to 4,000 epg

Question 24

What are the classifications of intensity of infection in S. mansoni?

Answer 24

light: 1-99 epg
moderate: 100-399 epg
heavy: more than or equal to 400 epg

Question 25

What is the gold standard for malarial parasites?

Answer 25

thick and thin smear

Question 26

What are the organisms detected by thick and thin smear?

Answer 26

Babesia, Hemoflagellates, Trypanosoma, Filarial nematodes (microfilaria)

Question 27

Used to determine if parasite is present; more sensitive; and is the first priority

Answer 27

thick blood smear

Question 28

Used to confirm the Plasmodium species present

Answer 28

thin blood smear

Question 29

Needs dehemoglobinisation by dipping in water

Answer 29

thick blood smear

Question 30

Fixed with methanol

Answer 30

thin blood smear

Question 31

What is the formula for parasitemia?

Answer 31

% parasitemia = (parasitized RBCs/total RBCs) x 100

Question 32

What should be done if the parasitemia is high?

Answer 32

examine 500 RBCs

Question 33

What should be done if the parasitemia is low?

Answer 33

examine 2000 RBCs

Question 34

Also called "scotch tape" swab

Answer 34

Cellophane Swab

Question 35

Primary parasite detected by cellophane swab

Answer 35

Enterobius vermicularis (pinworm) eggs

Question 36

Time of collection in cellophane swab

Answer 36

early in the morning before the patient washes or defecates

Question 37

How many negative tests should be done before pinworm infection is ruled out?

Answer 37

five (5)

Question 38

Where is E. vermicularis mostly recorvered?

Answer 38

Perianal swab; low recovery in stool

Question 39

What is the causative agent of taeniasis?

Answer 39

Taenia solium or Taenia saginata

Question 40

Segments that causes apolysis that releases eggs in the process

Answer 40

Proglottid

Question 41

Preferred sample for taeniasis

Answer 41

Stool

Question 42

Dissolves lipid content and other debris in concentration techniques

Answer 42

Ethyl acetate

Question 43

Easier to perform, routinely done, and more general

Answer 43

Sedimentation

Question 44

More recommended and cleaner procedure, but is more expensive

Answer 44

Flotation

Question 45

Filter paper with stool is dipped with water and the water is examined for filariform larva (L3)

Answer 45

Harada-Mori Filter Paper Culture

Question 46

Like Harada-Mori, but more stool is used and examines filariform larva (L3)

Answer 46

Baermann Funnel Culture

Question 47

Parasites examined by Harada-Mori and Baermann Techniques

Answer 47

Hookworm and Strongyloides

Question 48

Blood concentration technique for microfilaria (sedimentation/thick film)

Answer 48

Knott’s Concentration Technique

Question 49

What is the ratio of blood to reagent in Knott's concentration technique?

Answer 49

1mL venous blood + 10mL 2% formalin centrifuged 500xg 10 mins

Question 50

Used for schistosomes ; positive result is bulging of eggs

Answer 50

Circumoval Precipitin Test (COPT)

Question 51

Reagent and sample in COPT

Answer 51

lyophilized S. japonicum eggs + patient’s serum

Question 52

An inhibition test for trophozoites where the positive result is the non-bonding of dye

Answer 52

Sabin-Feldman Dye Test

Question 53

Infection detected by Sabin-Feldman Dye Test

Answer 53

Toxoplasma gondi infection

Question 54

How is Toxoplasma gondi transmitted?

Answer 54

transmitted through infection from cats and crosses the placental barrier, which makes it a fatal for pregnant and may cause cerebral defects and blindness

Question 55

Reagent for Sabin-Feldman Dye Test

Answer 55

toxoplasma + patient’s serum + methylene blue dye