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Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

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PARASITES, INTESTINAL OVA AND PARASITE EXAM (O & P EXAM), STOOL

Item Value
Available Stat? No
Performed by? Microbiology (Parasitology)
Sendout? no
Principle Trophozoites, cysts, and ova may be detected in stool of patients infected with parasites. A permanent stained smear and a concentration procedure is performed on each specimen.

The modified Iron Hematoxylin stain, which contains a carbol fuchsin acid-fast step, is used for the permanent stained smear. This allows detection of the acid - fast parasites, Cryptosporidium, Isospora, and Cyclospora in addition to other intestinal protozoa.
Container type Parasitology SAF Fixative Collection Vial
Collection Instructions Collect stool specimens using the Parasitology SAF Fixative Collection Kit, available from the Clinical Laboratory Support Services (206-8199). Follow instructions which accompany each kit. Only one specimen per 24 hour time period will be accepted and tested per patient.

Recommended screening procedure: Collect 3 stool specimens on separate days; one for every 2-3 days. Specimens must be submitted in SAF fixative and well mixed with fixative at time of collection for optimal recovery of parasites. When stool specimens stand without preservation, trophozoites disintegrate and the morphology of cysts and ova deteriorates.
Sample type Stool
Special instructions The following substances interfere with ova and parasite exam, and must NOT be used prior to collection of specimens:

Radiographic procedures barium sulfate
Antidiarrheal preparations bismuth, kaolin
Drugs sulfonamides, antibiotics,
antiprotozoal and
anthelminthic agents,
antacids, laxatives,
oils, and aluminum or
magnesium hydroxide
Enemas soap solution, water,
hypertonic salt solutions and irritants.


Wait at least seven days or more after barium procedures before collecting stool for examination.
Synonyms Intestinal Parasites;Stool;
Stability Specimens placed in SAF are stable at room temperature for 7 days.
References Garcia, LS, Diagnostic Medical Parasitology, ASM Press, 5th Ed., Washington, DC, 2007.
Last Updated 1/26/2009 4:07:34 PM
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