CHAPTER 2: Specimen Collection and Processing

Question 1

2 general components of O&P

Answer 1

Macroscopic and Microscopic

Question 2

Helminth stages

Answer 2

Cestodes
Eggs
Proglottids
Larvae (L1, L2, L3)
Adult worms
Nematodes
Trematodes

Question 3

What is the typical stool collection?

Answer 3

3 specimens that are:

1. collected every other day
2. total of (3 specimens) collected in 10 days

Question 4

Clean, wide-mouthed containers ENSURES?

Answer 4

moisture retention

Question 5

what is the specimen exception for Amebiasis diagnosis

Answer 5

6 specimens in 14 days is acceptable

Question 6

Specimen collection for patients with therapy of interfering substances

Answer 6

Collect specimen prior to therapy or

5-7 after completion

Question 7

What are the interfering substances?

Answer 7

Barium
Bismuth
Mineral Oil

Question 8

Specimen collection for patients with antibiotics or anti-malarial medication

Answer 8

Delayed for 2 weeks following therapy

Question 9

Standards in stool collection

Answer 9

Clean, watertight container w/ tight fitting lid
2-5g “size of a walnut”
Urine is not allowed to contaminate stool
Should not be retrieved from toilet bowl water

Question 10

Why stool specimens should not be contaminated by urine?

Answer 10

It may destroy parasites needed for diagnosis

Question 11

Why stool specimens should not be retrieved from toilet bowl water?

Answer 11

Toilet bowl water contains free-living protozoa and nematodes

Question 12

Parasite that can be destroyed by water (like eggs and amebic trophozoites)

Answer 12

Schistosome

Question 13

What else can contaminate the stool and makes it difficult for examination?

Answer 13

Toilet paper

Question 14

What labels and standards should be seen in a specimen container?

Answer 14

Patient's name
Identification number
Physician's name
Date and time
Age and sex
Zip lock bag for transport
Form of requisition paper
Indicating tests required
OTHERS:
Suspected diagnosis
travel history
clinical findings
prior infections

Question 15

In testing fecal specimen, liquid stool should be examined within how many minutes?

Answer 15

30 mins of passage

Question 16

In testing fecal specimen, semi-formed stool should be examined within how many hours?

Answer 16

1 hour of passage

Question 17

In testing fecal specimen, formed stool should be examined within how many hours?

Answer 17

24 hours following collection

Question 18

What should be done if the standard minutes for fresh examination is not met?

Answer 18

Specimen is placed into preservative by using fixatives.

Question 19

2 diagnosis of parasitic infections:

Answer 19

1. Definitive diagnosis

2. Presumptive diagnosis

Question 20

It demonstrates humoral immune response of the individual (antigen-antibody)

Answer 20

Presumptive diagnosis

Question 21

Actual demonstration of parasites and parasitic components

Answer 21

Definitive diagnosis

Question 22

In definitive diagnosis, tapeworms are?

Answer 22

segmented

Question 23

What are the segments or parasitic components of tapeworms?

Answer 23

Scolex
Neck
Proglottids

Question 24

Standard refrigerator temperature for stool specimen

Answer 24

3-5 celcius

Question 25

- It preserves morphology of protozoa, - prevent further development of helminth egg & larvae - for successful recovery of parasites

Answer 25

Fixative

Question 26

Ratio for fixative preservation

Answer 26

3:1

Question 27

What are the different kinds of fixatives for specimen preservation?

Answer 27

1. Formalin 2. Schaudinn solution 3. Polyvinyl Alcohol (PVA) 4. Merthiolate-idodine-formalin 5. Sodium acetate formalin (SAF)

Question 28

The all purpose fixative.

Answer 28

Formalin

Question 29

Percentage of formalin to preserve protozoan cysts

Answer 29

5%

Question 30

Percentage of formalin to preserve helminth eggs and larvae

Answer 30

10%

Question 31

3 advantages of formalin

Answer 31

easy to prepare preserves for several years long shelf life

Question 32

Disadvantages of formalin

Answer 32

does not preserve parasite morphology for permanent smears (FADE w/ TIME) Considered potential health hazard

Question 33

- A preservative that plastic powder acts as adhesive for stool slide staining. - often combined with?

Answer 33

``` Polyvinyl Alcohol (PVA) with Schaudinn solution ```

Question 34

A preservative used for staining that contains: - Zinc sulfate - copper sulfate - Mercuric chloride (as a base)

Answer 34

Schaudinn solution

Question 35

Advantage and disadvantage of PVA

Answer 35

Long shelf life at room temp. Mercuric chloride is a potential health problem

Question 36

Many laboratories choose 2 vial systems such as:

Answer 36

Formalin vial for concentration | PVA vial for stained slide

Question 37

A preservative that is: - M&I staining - fixation of intestinal protozoa, helminth eggs, and larvae - Thimerosal

Answer 37

Merthiolate-iodine-formalin

Question 38

A preservative that is: - an alternative for PVA/Schaudinn's - concentration and permanent smear - used with modified acid-fast stain (to detect coccidian oocysts)

Answer 38

Sodium Acetate Formalin (SAF)

Question 39

Disadvantages of SAF

Answer 39

adhesive properties are not good and needs Albumin not as clear morphology like mercury-base stained smear with iron hematoxylin is better

Question 40

The analytic phase of laboratory

Answer 40

Processing

Question 41

Important factors considered in specimen processing

Answer 41

Consistency and color

Question 42

3 distinct procedures for microscopic examinations

Answer 42

Direct wet preparation Concentrated wet preparation permanently stained smear

Question 43

A prep that has a drop of ___% saline on glass slide mixed with unfixed stool

Answer 43

Direct saline wet prep (0.85%)

Question 44

Lugol's or D Ántoni's formula

Answer 44

Direct Iodine wet prep

Question 45

It minimizes the refraction of glycerin

Answer 45

Malachite Green

Question 46

Used to clear fecal debri

Answer 46

Glycerin

Question 47

A prep that uses malachite green or green cellophane soaked in glycerin

Answer 47

Kato thick smear

Question 48

Kato thick smear is to be examined ____ mins

Answer 48

10-20 mins

Question 49

Kato thick smear is not for:

Answer 49

thin shelled eggs | protozoan cysts and trophs

Question 50

has the ability to: - detect small numbers of parasite - aggregate parasites present into a small volume of sample - remove as mush debris - can be performed on fresh or preserved stool

Answer 50

Concentration methos

Question 51

2 types of concentration

Answer 51

Sedimentation and Flotation

Question 52

Most widely used sedimentation technique and based on specific gravity

Answer 52

Formalin-ethyl- acetate sedimentation

Question 53

This is added to a saline washed formalin - fixed sample

Answer 53

Ethyl acetate

Question 54

Technique where parasites float with specific gravity of ____?

Answer 54

Zinc sulfate flotation technique (1.18-1.20)

Question 55

Added to specimen and centrifuge (can be skimmed)

Answer 55

Zinc sulfate

Question 56

The final procedure for O&P for confirmation and observe detailed features of protozoa by intracellular organelles staining

Answer 56

Permanent stain

Question 57

2 common stains for routine O&P

Answer 57

Trichrome (wheatly modification) | Iron hematoxylin