DIRECT FECAL SMEAR (Saline and lodine Wet Mount Preparations)

Question 1

is commonly used as a quick screening test to check for the presence of any intestinal parasite in humans and even in animals.

Answer 1

Direct Fecal Smear (DFS)

Question 2

DFS may be examined as a _______, or _____ and _____

Answer 2

wet mount, or can be dried and stained.

Question 3

are useful for detecting motile organisms.

Answer 3

Wet mounts

Question 4

Protozoa
are often detected via a direct fecal smear with_____ solution, and are best acquired from the surface of fresh feces, obtained via a fecal loop or thermometer, or from a swab of the rectum.

Answer 4

iodine

Question 5

________ that is present on the surface of feces should also be examined microscopically since many protozoa will get trapped there.

Answer 5

Mucus

Question 6

Fecal specimens
should be examined grossly for consistency (formed, soft, loose, or watery), and for presence of:

Answer 6

Mucus
Blood
larval or adult worms and
proglottids

Question 7

are more likely to be found in watery or loose specimens

Answer 7

Protozoan trophozoites

Question 8

predominate in formed or soft specimens

Answer 8

Cysts

Question 9

may be found in any type of fecal specimen.

Answer 9

Helminths or their eggs

Question 10

• may be more numerous in the last portion of stool and should be specifically sought in mucus

Answer 10

Protozoan trophozoites

Question 11

allow detection and observation of motile protozoa trophozoites and helminth larvae.

Answer 11

Direct saline wet mounts of fresh feces

Question 12

allow detection of parasites that do not concentrate well.

Concentration procedures increase the examiner’s ability to detect protozoa cysts and helminth eggs and larvae but are unsatisfactory for detecting protozoan trophozoites

Answer 12

Direct mounts of preserved specimens

Question 13

are useful for detection and morphologic examination of protozoan trophozoites and cysts.

Answer 13

Permanent stains

Question 14

The circumstances under which each procedure is performed varies depending on the type of specimen (4) submitted.

Answer 14

formed, soft, loose, or watery

Question 15

may be concentrated by simple centrifugation rather than by floatation or formalin-ethyl acetate concentration.

Answer 15

Watery specimens

Question 16

The direct wet mount may be omitted if the specimen is submitted in _____

Answer 16

preservatives

Question 17

should be examined by a concentration procedure, although improved yield has been demonstrated when a permanent stain is added to the work-up

Answer 17

formed specimens

Question 18

Advantagess of DFS

Answer 18

● Useful for detecting motile organisms.

● Protozoa are often detected via a direct fecal smear.

● Quick process

Question 19

Disadvantages of DFS

Answer 19

● Small size of the sample limits its usefulness.

● You may get inaccurate results.

● If your examination finds no evidence of a parasite but the patient actually harbors the parasite, then the results are called a false negative result.

● False negative results are common with direct fecal smears.

Question 20

MATERIALS for DFS

Answer 20

● Microscope slides
● Cover slips
● Sodium chloride solution
● Lugol’s lodine Solution
● Wooden applicator
● Fresh stool
● Gloves

Question 21

Percent of NSS

Answer 21

.85%

Question 22

Why do we need to mix the stool beforehand

Answer 22

For even distribution of suspected parasites

Question 23

SLIDES
2 types of specimen prep

Answer 23

● Saline Specimen Prpn.
● lodine Specimen Prpn

Question 24

Used to onserve for the motility of parasite

Answer 24

NSS

Question 25

Trophozoites and cysts can be seen by using

Answer 25

NSS

Question 26

Can only see cysts

Answer 26

Lugol’s iodine solution

Question 27

Purpose of Lugol’s iodine

Answer 27

Used to visualize and enhance the morphology of internal structures

Question 28

Trophozoites are toxic to

Answer 28

Iodine

Question 29

Used to detect Ovas

Answer 29

Concentration Method

Question 30

● A drop of warm____ or ____ is placed over a clean microscopic slide.

● About____ of stool sample should be taken and mixed with soln placed over the slide.

●_____ is placed avoiding air bubbles.

● Examined under Microscope.

Answer 30

Saline or Lugol’s lodine

2mg

Coverslip

Question 31

● The fecal smear may be examined in its wet state by simply placing a cover slip over the drop of wet fecal material.

● This method is most useful looking for_____ which can be observed by their characteristic movement and appearance.

Answer 31

Wet Mount Technique

trophozoites

Question 32

Wet Mount Technique

Procedure (3)

Answer 32

Collect sample from container

Add sample to slide

Place cover slip on sample

Question 33

DFS

About______ of stool (amount forming a low cone at the tip of an applicator stick) is comminuted thoroughly with a drop of ______% sodium chloride solution (NSS) and then covered with a cover slip.

Answer 33

2 mg

0.85%

Question 34

This is a routine method of stool examination primarily useful in the detection of motile protozoan trophozoites

Answer 34

DFS

Question 35

DFS

In this preparation, the trophozoites appear very pale and transparent.

Trophozoites can be stained to demonstrate the nuclear morphology using__________ solution

Answer 35

Nair’s buffered methylene blue (BMB)

Question 36

T or F

Protozoan cysts can also be seen in a DFS.

Answer 36

True

Question 37

A weak iodine solution ______ or ______ can be used as a temporary stain to demonstrate nuclei

Answer 37

(Lugol’s solution or D’Antoni)

Question 38

The cytoplasm will stain golden yellow, the nucleus will be pale and refractile, and the glycogen will be deep brown.

Helminth eggs and larvae can also be detected using this preparation.

Because the amount of stool used in DFS is very small, light infections may not be detected.

Answer 38

Iodine

Question 39

a tool to measure cysts and ova, will be useful in specific species identification.

Answer 39

Micrometry