Fecalysis- Notes PDF

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Summary

Lecture notes summarized by KASC, RMT...

Description

is the most common procedure performed in Parasitology Area. Two general components of routine fecal analysis:  MACROSCOPIC EXAMINATION  MICROSCOPIC EXAMINATION General considerations in stool examination • Time factor in examination – Watery, liquid, diarrheic specimen: 30 mins – Formed specimens: >1 hour or within the day If not possible, stools should be preserved. Note: The ideal specimen for examination is the freshly collected stool specimens. The specimen must be fixed in the preservative for at least 30 minutes before processing begins.

Preservatives Fixatives – are substances that preserve the morphology of protozoa and prevent further development of helminth eggs and larvae Recommended ratio of fixatives: 3 parts fixative : 1 par partt of stool sample

Types of Preservatives

Formalin – all-purpose fixative for the recovery of protozoa and helminths. – 5% conc. for protozoans – 10% conc. for helminths and larvae

Advantages of Formalin Formalin:: • Easy to prepare • Preserves up to several years • Long shelf life • Suitable for concentration procedures. • Suitable for acid-fast and safranin stains. • Compatible with immunoassay kits. Disadvantages of For Formalin: malin: • Inadequate preser preservation vation of morphology of protozoan trophozoites • can interfere with PCR; cyst and helminth eggs may fade with time

Polyvinyl alcohol ((PVA) PVA) – Most often combined with Schauddin (cont (contains ains mercuric chloride, zinc su sulfate, lfate, copper sulfate) as a base – With plastic powder used as adhesive in preparing slides for staining Advantages of PVA: • Preserves protozoans & helminths • Long shelf-life • Used in preparing permanent st stained ained smears (solution preserves organism and makes them adhere to slides) Disadvantages of PVA: • possible health ris riskk due to mercuric chloride components of Schauddin • inadequate preservation of morphology of helminth eggs and larvae • less suitable for concentration procedures; cannot be used with immunoassay kits

FECALYSIS: Macroscopic Examination ||2019-2020

Stool examination (Fecalysis)

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Sodium Acetate Formalin (SAF) – Used as preservative in concentration technique and permanent stained smears. Advantages of SAF: • Easy to prepare • Long shelf-life • Fixatives for samples stained with modified acid-fast stains • Suitable for both concentration procedures and preparation of permanent stained smears. • Compatible with immunoassay kits Disadvantages of SSAF: AF: • Requires additive for adhesion of specimens to slides. • Protozoa is not cclear lear in permanent stains • Choice of permanent stains should be made for this fixative

Modified PVA – utilizes subtitute compounds containing copper sulfate or zinc sulfate • Used for concentration and permanent stains

Alternati Alternative ve single single-vial -vial systemsdeveloped by manufacturers that are free from formalin and mercury • Used for concentration techniques and permanent stained smears.

Macroscopic Examination  Evaluation of:  Color  Consistency  Generally, any gross abnormalities are noted.

Merthiolate Merthiolate-iodine-iodine-iodine-formaldehyde formaldehyde (MIF) Advantages Advantages: • Components both fix and stain organisms • Easy to prepare • Suitable for concentration procedures Disadvantages of MIF: • Inadequate preservation of morphology of protozoan trophozoites. • Iodine may cause dis distortion tortion of protozoa

 Or the degree of moistur moisturee  Serves as an indication of the type of potential parasites present  Example: Well-formed, Soft, Watery  NORMAL: Well-formed

FECALYSIS: Macroscopic Examination ||2019-2020

Consiste Consistency ncy

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Color  May indicate an underlying condition  Example: Brown, Black, Yellow, Red  NORMAL: Brown

FECALYSIS: Macroscopic Examination ||2019-2020

BRISTOL STOOL CHART

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