LESSON 3 DIRECT FECAL SMEAR (DFS) AND CELLULOSE TAPE SWAB (CTS)

• Wet mounts

• Concentration techniques

• Permanently stained smear

• Culture

The presence of parasites with intestinal origin is primarily identified through direct examination of stool using:

3 specimens

EXAMINATION OF FECAL SPECIMEN

• How many stool specimens are considered the minimum for an adequate O&P examination?

10 days

EXAMINATION OF FECAL SPECIMEN

• Within how many days should the three stool specimens be collected for O&P exam?

up to 7 specimens

EXAMINATION OF FECAL SPECIMEN

• For certain parasites like Giardia lamblia and Strongyloides stercoralis, how many O&P examinations are needed for optimal detection?

Wet mounts

EXAMINATION OF FECAL SPECIMEN

• small amount of stool only

Wet mounts

EXAMINATION OF FECAL SPECIMEN

• Its purpose is to detect motile trophozoites, cyst, ova, and larvae

Wet mounts

EXAMINATION OF FECAL SPECIMEN

• Can be done for rapid initial diagnosis of intestinal parasite

Wet mounts

EXAMINATION OF FECAL SPECIMEN

• Commonly done in clinics and hospitals

Wet mounts

EXAMINATION OF FECAL SPECIMEN

• What we call the fecalysis in the lab request of the doctor

Concentration technique

EXAMINATION OF FECAL SPECIMEN

• If the patient has very low parasite load infection, the doctor might prefer doing a __________

Concentration techniques

EXAMINATION OF FECAL SPECIMEN

• Its purpose is to improve the sensitivity of the stool examination

Permanently stained smear

EXAMINATION OF FECAL SPECIMEN

• The stool sample will be the one to undergo smearing, fixation, and staining

Permanently stained smear

EXAMINATION OF FECAL SPECIMEN

• Significant for the detailed microscopic study of protozoan morphology

Culture

EXAMINATION OF FECAL SPECIMEN

• If you want the parasite to grow and multiply, especially for those parasites that are difficult to see

Culture

EXAMINATION OF FECAL SPECIMEN

• Can be done to increase their detection and it is also used in research and studies

• Gross Examination

• Fecal Techniques

• Microscopic Techniques

PHASES IN STUDYING AND ANALYZING STOOL SAMPLE

Gross Examination

PHASES IN STUDYING AND ANALYZING STOOL SAMPLE

• characteristic of the stool

Fecal Techniques

PHASES IN STUDYING AND ANALYZING STOOL SAMPLE

• analysis, procedural

Microscopic Techniques

PHASES IN STUDYING AND ANALYZING STOOL SAMPLE

• to detect presence of parasite

3g - 5g

INTERPRETATION OF STOOL EXAMINATION

• What is the recommended amount of stool specimen?

• Color

• Consistency

INTERPRETATION OF STOOL EXAMINATION

• Macroscopic Examination includes:

• RBC

• WBC

• fat globules

• bacteria

• parasites

INTERPRETATION OF STOOL EXAMINATION

• What are the components observed during microscopic examination of stool?

Black or melena

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Upper GI bleeding

Black or melena

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Iron therapy

Black or melena

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Charcoal

Black or melena

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Bismuth (antacids)

Red

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Lower GI bleeding

Red

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Beets and food coloring

Red

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Rifampin

• Pale yellow, white, gray

• Bulky/frothy

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Bile-duct obstruction

Pale yellow, white, gray

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Barium sulfate

Green

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Biliverdin/oral antibiotics

Green

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Green vegetables

Bulky/frothy

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Pancreatic disorders

Ribbon like

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Intestinal constriction

Mucus or blood-streaked mucus

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Colitis

Mucus or blood-streaked mucus

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Dysentery

Mucus or blood-streaked mucus

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Malignancy

Mucus or blood-streaked mucus

MACROSCOPIC STOOL CHARACTERISTICS

• Color / Appearance: _______

• Possible Cause: Constipation

Color

MANNER OF REPORTING

• What parameter in macroscopic examination refers to the appearance of stool

Consistency

MANNER OF REPORTING

• What parameter in macroscopic examination describes the form or texture of stool?

Average number per 10 HPF

MANNER OF REPORTING

• How are RBCs reported in stool microscopy?

Average number per 10 HPF

MANNER OF REPORTING

• How are WBCs reported in stool microscopy?

Rare, few, moderate, many per LPF

MANNER OF REPORTING

• How is bacteria reported in stool microscopic examination?

• 10% formalin

• MIF

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Which stool fixative is used for direct wet mount and concentration but NOT for permanent stained smear?

• Schaudinn’s fluid

• Polyvinyl alcohol (PVA)

• Modified PVA

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Which fixative is used ONLY for permanent stained smear?

Modified PVA

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• What is a modified version of PVA used for permanent staining?

• 10% formalin

• MIF (Merthiolate-iodine-formalin)

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Which fixative allows direct wet mount and concentration but not permanent staining?

• None (Fresh stool)

• Schaudinn’s fluid

• PVA

• Modified PVA

• SAF

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Which fixatives are used for permanent stained smear?

• Fresh stool

• 10% formalin

• MIF

• SAF

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Which fixatives are used for direct wet mount?

• None (Fresh stool)

• SAF

COMMONLY USED STOOL FIXATIVES AND EXAMINATION TECHNIQUES

• Fixative for all methods?

• Wet Smear Preparation

• Iodine Smear Preparation

DIRECT FECAL SMEAR (DFS)

Normal saline solution (NSS)

WET SMEAR PREPARATION

• What solution is placed on the slide before adding the stool sample?

Applicator stick

WET SMEAR PREPARATION

• What tool is used to collect and transfer the stool sample to the slide?

Low-power (LPO) and High-power (HPO)

WET SMEAR PREPARATION

• Under what objectives should the wet smear be examined?

3 × 2 inches

WET SMEAR PREPARATION

• What is the standard size of the glass slide used in wet smear preparation?

0.85% NSS

WET SMEAR PREPARATION

• What is the required concentration of NSS for wet smear preparation?

22 mm

WET SMEAR PREPARATION

• What is the standard size of the cover slip used?

Comminuted

WET SMEAR PREPARATION

• What term is used to describe a stool sample that is finely broken down or crushed into very small pieces?

Lugol’s iodine

IODINE SMEAR PREPARATION

• What reagent is added to the wet smear slide in iodine smear preparation?

At the edge of the cover slip

IODINE SMEAR PREPARATION

• Where is Lugol’s iodine placed in iodine smear preparation?

Low-power (LPO) and High-power (HPO)

IODINE SMEAR PREPARATION

• Under what objectives should the iodine smear be examined?

D’Antoni’s formula

IODINE SMEAR PREPARATION

• What is another name/formula associated with Lugol’s iodine?

Motility of trophozoites

IODINE SMEAR PREPARATION

• What is observed in NSS preparation that is NOT seen in iodine preparation?

Cyst (nucleus and morphology)

IODINE SMEAR PREPARATION

• What structure is best observed in iodine preparation?

Cellulose Tape Swab Technique or Graham’s Scotch Adhesive Tape Swab

CELLULOSE TAPE SWAB (CTS)

• What method is also known as the Scotch Tape Swab Method?

Enterobius vermicularis

CELLULOSE TAPE SWAB (CTS)

• What parasite is best diagnosed using the Cellulose Tape Swab technique?

Toluene or xylol

CELLULOSE TAPE SWAB (CTS)

• What substance may be added between the tape and slide to clear the preparation?

3

CELLULOSE TAPE SWAB (CTS)

• For how many consecutive days should CTS specimens be collected?

Late at night (10–11 PM)

CELLULOSE TAPE SWAB (CTS)

• When is an alternative time to collect CTS specimen if morning collection is not possible?

4–6 or 5

CELLULOSE TAPE SWAB (CTS)

• How many consecutive negative tape tests are required to rule out infection?

Taenia spp. and Schistosoma mansoni

CELLULOSE TAPE SWAB (CTS)

• Aside from Enterobius, what other parasites may be recovered using CTS?

Perianal area

PRINCIPLE

• Where are Enterobius vermicularis eggs commonly deposited?

cellophane tape procedure

PRINCIPLE

• What method is used to collect Enterobius vermicularis eggs from the perianal area?

Within 4–6 hours

PRNCIPLE

• How fast do Enterobius vermicularis eggs become infective?

Embryonated egg

PRNCIPLE

• What stage of Enterobius egg is infective to humans?

2 ½ –3 inches

LABORATORY PROCEDURE

• What is the recommended length of transparent tape used in CTS?

Perianal folds (right and left)

LABORATORY PROCEDURE

• Where should the sticky side of the tape be pressed?

Toluene

LABORATORY PROCEDURE

• What is added to clear the preparation?

Low-power objective (LPO)

LABORATORY PROCEDURE

• Under what objective is the specimen examined?