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Clinical Parasitology > Laboratory: Concentration Techniques > Flashcards

Laboratory: Concentration Techniques Flashcards

1
Q

Used for light parasitic infection, when number of ova or adult worm is found in the feces in minimal portion or number

A

Concentration Techniques

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2
Q

Minimal parasitic infection can result to true-positive in DFS. True or False?

A

False, minimal parasitic infection results to false-negative in DFS

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3
Q

Purpose of Concentration Techniques

A

Aggregate parasites present into a small volume of the sample and to remove as much debris as possible that might hinder the laboratory technician’s ability to see any parasites present clearly

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4
Q

Type of sample used in concentration techniques

A

Fresh/preserved

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5
Q

Two Types of Concentration Technique

A

Flotation Method
Sedimentation Method

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6
Q

In this technique, parasites are less dense than the solutions used and during centrifugation, they float to the surface

A

Flotation Method

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7
Q

Reagents used in Flotation Method

A

Zinc sulfate
Magnesium sulfate
Brine
Sugar

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8
Q

The reagents in Flotation Techniques should have what kind of specific gravity, higher or lower?

A

Higher

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9
Q

How many minutes before parasites distort or shrinkage of cysts and eggs occur?

A

20 minutes

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10
Q

Flotation Techniques are mostly used on what type of parasites?

A

Nematode eggs (except T. trichiura and C. philippinensis)
Protozoan cysts

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11
Q

The ratio or comparison between the density of a certain substance to the density of another substance

A

Specific Gravity

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12
Q

Higher SG, _; Lower SG, _

A

Higher concentration
Lower concentration

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13
Q

Specific Gravity of water

A

1.00

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14
Q

Flotation Technique that uses saturated table salt solution

A

Brine Flotation Method

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15
Q

Components of saturated brine solution

A

NaCl - 40g
Distilled water - 100mL

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16
Q

Eggs of _ and _ become badly shrunken in Brine Flotation Method

A

Hookworm
Schistosoma

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17
Q

Brine Flotation Method is not useful for operculated eggs like Ascaris, Trichinella and Raillietina. True or False?

A

False, operculated eggs such as Opistorchis, Clonorchis and Heterophyids

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18
Q

Ideal Specific Gravity for Flotation Technique

A

1.18-1.20

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19
Q

Who developed Zinc Sulfate Flotation Technique and when?

A

Faust, 1938

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20
Q

Percentage of Zinc Sulfate solution used

A

33%

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21
Q

Most widely-used reagent

A

Zinc Sulfate Solution

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22
Q

To ensure detection of all possible organisms in Zinc Sulfate Flotation Technique, both _ and _ must be examined

A

Surface film
Sediment

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23
Q

SG used for fresh stool in Zinc Sulfate Flotation Technique

A

1.18

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24
Q

SG used for preserved stool in Zinc Sulfate Flotation Technique

A

1.20

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25
Q

Components of Zinc Sulfate Solution

A

Zinc Sulfate (dry crystal) - 330g
Distilled water - 670 mL

26
Q

Type of stool not ideal for Zinc Sulfate Flotation Technique

A

Fatty stool

27
Q

Zinc Sulfate is what type of solution that causes lysis of parasites?

A

Hypertonic

28
Q

Considered best for the recovery of coccidian oocysts mainly Cryptosporidium spp

A

Sheather’s Sugar Flotation Technique

29
Q

What solution is used in Sheather’ Sugar?

A

Sugar boiled in phenol

30
Q

SG of sugar boiled in phenol

A

1.27

31
Q

Cryptosporidium spp. reacts to modified acid-fast stain and turns from _ to _?

A

Bright-red to purple

32
Q

Specie of Cryptosporidium in animals and humans

A

C. parvum

33
Q

Specie of Cryptosporidium primarily in humans

A

C. hominis

34
Q

In this technique, parasites are concentrated in the sediment of the tube following centrifugation and the sediment is examined microscopically

A

Sedimentation Techniques

35
Q

Reagents in Sedimentation Technique have what type of specific gravity, higher or lower?

A

Lower

36
Q

In Simple Gravity Sedimentation Technique, this is added to stool to allow parasites to settle down by gravity

A

Tap water

37
Q

What parasite hatches quickly in tap water?

A

Schistosoma spp.

38
Q

To prevent hatching of eggs in Simple Gravity Sedimentation Technique, _ is added

A

NSS (Normal Saline Solution)

39
Q

This solution enhances sedimentation or settling of parasites

A

Glycerinated water

40
Q

Percentage of glycerin solution in tap water

A

0.5%

41
Q

Sediments can be preserved in _ or _

A

5% formol-saline
10% formalin

42
Q

Recommended for the recovery of Trichuris, Capillaria and Schistosoma

A

Acid Ether Concentration Techniques

43
Q

Used to dissolve albuminous
material

A

Hydrochloric acid

44
Q

Ether is flammable and explosive, it can be replaced with?

A

Ethyl acetate

45
Q

Dissolves neutral fats/lipids and carbohydrates in stool

A

Ether or ethyl acetate

46
Q

Percentage of hydrochloric acid in Acid Ether CT?

A

40%

47
Q

Loss of parasite to the plug of debris and destruction of protozoan cysts is possible in Acid Ether CT. True or False?

A

True

48
Q

Components of Hydrochloric acid

A

Concentrated hydrochloric acid - 40mL
Distilled water - 60mL

49
Q

Most widely used sedimentation technique. Useful in the recovery of both helminth eggs and protozoan
cysts; can be done with formalin-preserved and PVA-preserved samples

A

Formalin Ether/Ethyl Acetate CT

50
Q

All-purpose fixative

A

10% formalin

51
Q

Morphology is also better preserved in _ than in
_

A

Formalin than in PVA

52
Q

Sediments from FECT can be stored for a long period of time. True or False?

A

True

53
Q

Component of 10% Formalin

A

Concentrated formaldehyde - 10mL
Distilled water - 90mL

54
Q

Recommended for the better identification of protozoan cysts

A

Merthiolate Iodine Formalin Ether Concentration Technique

55
Q

Stain used in MIF Ether CT

A

Merthiolate and Iodine

56
Q

Components of Lugol’s Iodine Solution

A

Iodine powdered crystals - 5g
Potassium iodide - 10mL
Distilled water - 90mL

57
Q

Components of Stock Merthiolate Formaldehyde Solution

A

Distilled water - 50mL
Tincture of Merthiolate - 40mL
Glycerin - 1mL
Formaldehyde - 5mL

58
Q

It is necessary to use _ since this contains eosin which stains protozoan cysts and trophozoites along with iodine

A

Thimerosal or
Tincture of Merthiolate

59
Q

Sedimentation techniques are also known as

A

Indirect Wet Mount

60
Q

Size of coverslips

A

22x22 mm

61
Q

Why are sedimentation methods more recommended?

A

They are more efficient and easier to perform accurately

Clinical Parasitology (13 decks)

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