Ova and Parasite (O&P) Examinations

Microscopic Examination - Ova and Parasite Examination

The direct wet smear should not be performed when the specimen (already preserved) arrives in the laboratory. No organism motility will be visible and the technical time is better spent performing the concentration and permanent stained smear.
As mentioned above, some workers prefer to make the saline and iodine mounts on separate slides and on 2- by 3-in. slides. Often there is less chance of getting fluids on the microscope stage if separate slides are used (less total fluid on the slide and under the coverslip) or if larger slides are used.
The microscope light should be reduced for low-power observations, since most organisms will be overlooked with bright light. This is particularly true when the preparation is being examined without the use of iodine. Illumination should be regulated so that some of the cellular elements in the feces show refraction. Most protozoan cysts and some coccidian oocysts will be refractile under these light conditions.