STOOL FIXATIVES AND CELLOPHANE TAPE METHOD Flashcards
7 fixatives
● Formalin
● Merthiolate-iodine-formalin (MIF)
● Polyvinyl Alcohol (PVA)
● Sodium acetate-acetic acid-formalin (SAF)
● Schaudinn’s Fixative
● Modified PolyvinylAlcohol (Modified PVA)
● One-vial Fixatives
______________ formalin are commonly used
5% and 10%
5% of formalin are ___________
protozoan cysts (not including trophozoites)
10% of formalin are _____________
helminth eggs and larva
describe formalin
5PLEA
● 5% and 10% formalin are commonly used
● preserves specimens up to several years
long shelf-life
● easy to prepare
● all-purpose fixative
______ and ____________ are staining components
Merthiolate and iodine
preservative (actual fixative
formalin
____________ is also known as thimerosal
Merthiolate
Main purpose: melthiolate-iodine formalin
fixation of intestinal protozoans, helminth
eggs and larvae
There is a possibility that you will encounter difficulty in the
specific identification of protozoans
B. MERTHIOLATE-IODINE-FORMALIN (MIF)
A plastic powder that can act as an adhesive for the stool
specimen when preparing slides for staining
C. POLYVINYL ALCOHOL (PVA)
● Has good adhesive property
C. POLYVINYL ALCOHOL (PVA)
Suitable for permanent smears that are stained with
trichrome
C. POLYVINYL ALCOHOL (PVA)
good in preserving protozoan trophozoites and cysts
○ But not good for helminth eggs, larvae, poxidia,
and microsporidia
HLPM
C. POLYVINYL ALCOHOL (PVA)
used in preparation of permanent stained smear
C. POLYVINYL ALCOHOL (PVA)
● long shelf life when stored at RT
C. POLYVINYL ALCOHOL (PVA)
● concentration technique can be performed with
PVA-preserved specimen but not as effective as formalin
C. POLYVINYL ALCOHOL (PVA)
two vial system in laboratories
one portion for the stool specimen and other for the polyvinyl alcohol (PVA)
similar to PVA as to what it preserves, what is suitable or not when used
and having mercuric chloride as one of its component
SCHAUDINN’S FIXATIVE
poor adhesion of liquid or mucoid specimens to slides
SCHAUDINN’S FIXATIVE
● used for performing concentration techniques and
permanent stained smears
● long shelf-life
● easy to prepare
● mercury-free
Sodium acetate acetic acid formalin
Sodium acetate- acetic acid formalin is suitable for
Acid fast stain
○ Safranin
○ Chromotrope stain
Allow the additive to be spread on the slide before
putting the specimen
SODIUM ACETATE-ACETIC ACID FORMALIN (SAF)
● Another alternative for mercury based fixative (no mercury)
● similar to SAF wherein it can be used for concentration
methods and permanent stained smears
● uses a substitute compound (zinc sulfate or copper sulfate
F. MODIFIED POLYVINYL ALCOHOL
similar to SAF wherein it can be used for concentration
methods and permanent stained smears
F. MODIFIED POLYVINYL ALCOHOL
uses a substitute compound (zinc sulfate or copper sulfate)
MODIFIED POLYVINYL ALCOHOL
PVA gives more better results
F. MODIFIED POLYVINYL ALCOHOL
