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http://loudoun.nvcc.edu/vetonline/VET133/fecal flotation.htm
Reporting and interpreting results
This test is qualitative and the numbers of ova seen are not necessarily an indication of the severity of worm burden.
Positive results are reported as to the type of ova, oocysts, cysts, or larva seen. Ideally genus and species is fabulous information to have but it is not always possible. Most treatment protocols can be devised even with only general information as to the ova type. You should be as specific as you can, but usually terms such as roundworm, hookworm, whipworm, capillarid, trichurid, strongyle, taenid, etc are acceptable to many veterinarians in practice.
False negative results are possible:
Therefore you should report negative findings as “no ova (or oocysts) seen” or “NOS” as it is sometimes abbreviated. Other abbreviations commonly used are NPS (no parasites seen) or NVP (no visible parasites). If you tell the owners the fecal test was negative, they will assume that the pet is free of parasites, which may not be true.
If occult parasitism is suspected, the veterinarian may elect to treat anyway even if findings are NOS. Sequential fecal flotations, usually at least 3, may be needed over several days time to verify the findings.More than one type of flotation solution may be needed also. Other tests should also be considered in the work up, such as fecal smear techniques, acid fast stain preparations, ELISA testing, and fecal sedimentation to rule out organisms that may not be detected by fecal flotation.
Reporting and interpreting results
This test is qualitative and the numbers of ova seen are not necessarily an indication of the severity of worm burden.
Positive results are reported as to the type of ova, oocysts, cysts, or larva seen. Ideally genus and species is fabulous information to have but it is not always possible. Most treatment protocols can be devised even with only general information as to the ova type. You should be as specific as you can, but usually terms such as roundworm, hookworm, whipworm, capillarid, trichurid, strongyle, taenid, etc are acceptable to many veterinarians in practice.
False negative results are possible:
- The parasite may be in the prepatent period
- The specimen is old and the organisms have deteriorated or hatched out
- The ova or oocyst may have been damaged by the procedure-if incubation was too long or if the specific gravity of the solution was too high
- The parasite may be suppressed in reproduction
- Ova may be only sporadically produced and the specimen was tested on a less productive day
- Diarrhea may dilute the concentration of ova
- Mucus may interfere with the flotation if it is not dispersed in the solution during the procedure
Therefore you should report negative findings as “no ova (or oocysts) seen” or “NOS” as it is sometimes abbreviated. Other abbreviations commonly used are NPS (no parasites seen) or NVP (no visible parasites). If you tell the owners the fecal test was negative, they will assume that the pet is free of parasites, which may not be true.
If occult parasitism is suspected, the veterinarian may elect to treat anyway even if findings are NOS. Sequential fecal flotations, usually at least 3, may be needed over several days time to verify the findings.More than one type of flotation solution may be needed also. Other tests should also be considered in the work up, such as fecal smear techniques, acid fast stain preparations, ELISA testing, and fecal sedimentation to rule out organisms that may not be detected by fecal flotation.