The definite and exact diagnosis of protozoa is possible using high magnification objective
lenses, provided that suitable stained smears are prepared. Therefore, the appropriateness of both
fixative and staining methods to the species of parasite, which is the main objective of this study, is important. In this study, five various
fixatives including (
Merthiolate iodine formalin) MIF, (
Sodium acetate-
acetic acid formalin)
SAF, (
Polyvinyl alcohol) PVA,
formalin and schaudinn and four types of stains including
Hematoxylin I,
Hematoxylin II, Trichrome and
Carbol-fuchsin were prepared using standard procedures. After the smears of stool samples containing Giadria lamblia
cyst were prepared and kept for 24 h in various
fixatives, the study was carried out using the four above-mentioned stains by changing the ingredients and time as well as by repeating the experiments. After fixing and staining all the smears in identical conditions along with the implementing interferences in the staining process, the following results were eventually obtained considering the morphologic indexes and negative and positive scores (from 1 to 20):
formalin with 17 scores in
hematoxylin I staining,
formalin and
SAF with 15 and 14 scores, respectively in
Hematoxylin II staining, MIF with 13 scores in Trichrome staining and
SAF, PVA, MIF with 11.5, 11.5 and 11 scores, respectively in
carbol-fuchsin staining were found to be the best
fixatives.
Hematoxylin I staining using
formalin fixative with 17 scores showed the best result while the maximum score for
Carbol-fuchsin staining was 11.5 showing a necessity for more expenditure, time and expert cooperation to reach ideal results.