Definitive diagnosis of the intestinal parasites requires the demonstration of the organisms or eggs in
feces or tissues. Stool specimens should be preserved and stained and microscopically examined.
• Stool samples were collected from patients complaining gastro-intestinal tract.
• Carmoisine red food color powder was dissolved in 2 solutions, sodium acetate acetic acid formalin
(C-SAformalin) solution, and 10% formal saline (C-10% formal saline) .
• Merthiolate-iodine-formalin (MIformalin) solution was prepared, (control solution).
• Eleven stool suspensions were prepared from one stool sample directly after the passage , 5 for each
serially diluted solution which mentioned above, and one for MIformalin solution.
• The suspensions of 64 positive stool samples were selected to this study and subjected to periodic
examination which programmed according to the schedule during one year.
• C-10% formal saline was inadequate in preservation of protozoan trophozoites.
• The most appropriate concentration of C-SAformalin solution was 2%wet/vol, this solution has the
ability to preserve the amoeba organisms( trophozoites and cysts ),Chilomastix mesnili (trophozoite
and cyst) ,Giardia lamblia (trophozoite and cyst), helminth eggs and the human elements for one
year when suspended in this solution, at the same time it has the ability to stain the parasitic and non
parasitic findings which mentioned above very efficiently.
• The protozoan trophozoites, protozoan cysts and leucocytes these cells were showed various levels of
stain uptake. All C-SAformalin solutions which were stored for periods between one day up to 18
months showed the same preservation and staining capability
The C-SAformalin solution with 2% wt/vol. concentration has proved to be highly efficient in
preservation for one year and staining of the intestinal protozoa (trophozoites and cysts), helminth eggs
and humane elements, which may be found in stool specimens.