TABLE A5.
Computer comments
| Result or situation | Report comment(s) | Interpretation or discussion |
|---|---|---|
| Submission of stool specimens | ||
| Submission of a single stool specimen for ova and parasite examination | One stool specimen is not sufficient for the recovery of intestinal parasites (only a 50% recovery); 2 specimens are recommended, while 3 offer the best chance of organism recovery | While 3 specimens collected over a 10-day period are the best approach, receipt of 2 specimens is acceptable |
| Submission of 2 stool specimens for ova and parasite examination | Although submission of 2 stool specimens is acceptable, 3 specimens collected over a 10-day period provide the best approach for organism recovery | While 2 specimens are now considered acceptable, 3 specimens will allow the most complete percentage recovery of intestinal parasites present |
| Examination of fecal specimens | ||
| No parasites seen | Antibiotics such as metronidazole or tetracycline may interfere with the recovery of intestinal parasites, particularly the protozoa | If a patient is symptomatic and intestinal parasites are suspected, this comment may be helpful for the physician, particularly if the patient has received any of these antibiotics |
| Yeasts, budding yeast, and/or pseudohyphae | Reports of yeasts may or may not be clinically relevant due to possible specimen handling delays prior to fixation | Because yeasts can continue to grow within the stool prior to fixation, the results from the permanent-stain smear may or may not be clinically relevant; quantitate cells if the number is moderate or many or the cells are packed |
| Trophozoites containing ingested RBCs (Entamoeba histolytica) | Pathogenic; cause of amoebiasis | A positive result is based on the presence of ingested RBCs within the trophozoite's cytoplasm and/or a fecal immunoassay specific for the pathogen is positive (Entamoeba histolytica positive) |
| Trophozoites containing no ingested RBCs and/or cysts (Entamoeba histolytica/E. dispar group) | Differentiation between the pathogen Entamoeba histolytica and the nonpathogen Entamoeba dispar is not possible based on organism morphology; if ingested RBCs are not seen or cysts are present, you will be unable to differentiate the two organisms You will be unable to determine pathogenicity from the organism's morphology or from the patient's clinical condition, and treatment may be appropriate |
A fecal immunoassay specific for the pathogen, Entamoeba histolytica, can be performed on fresh stool to separate out E. histolytica and E. dispar
An immunoassay for the Entamoeba histolytica/E. dispar group complex will not differentiate the true pathogen, Entamoeba histolytica The fecal immunoassay specific for the pathogen Entamoeba histolytica requires fresh stool for testing (this can be added as another comment if you offer the differentiation test; see the entry below) |
| Differentiation of E. histolytica from E. dispar | To determine the presence or absence of pathogenic Entamoeba histolytica, submit a fresh stool specimen | The fecal immunoassay specific for the pathogen Entamoeba histolytica requires fresh stool for testing |
| Blastocystis spp. | Blastocystis spp. contain ~10 human subtypes, none of which can be differentiated on the basis of organism morphology; some are pathogenic and some are nonpathogenic; if no other pathogens are found, Blastocystis may be the cause of patient symptoms and other organisms capable of causing diarrhea should also be ruled out | Until there are testing options to differentiate between the pathogenic and nonpathogenic subtypes, it is important that physicians know that some strains of Blastocystis are pathogenic; quantitate these organisms (rare, few, moderate, many, packed) |
| Giardia lamblia (other names which refer to the same organism, Giardia lamblia, include Giardia intestinalis and Giardia duodenalis) | Pathogenic | If fecal immunoassays are performed, the testing of two separate stools (collected at least 1 day apart) is recommended before the patient is considered negative; the testing of two stools is not required for Cryptosporidium spp. |
| Entamoeba hartmanni, Entamoeba coli, Endolimax nana, Iodamoeba bütschlii, Chilomastix mesnili, Pentatrichomonas hominis, Enteromonas hominis, Retortamonas intestinalis, trophozoites and/or cysts | Nonpathogenic; treatment is not recommended; however, recovery of these organisms indicates that the patient has ingested something contaminated with fecal material (by the same infectivity route for pathogens) | It is important to report nonpathogens; a patient may be infected with one or more pathogen(s) not yet found |
| Microsporidia (fecal and urine specimens), Enterocytozoon bieneusi, Encephalitozoon intestinalis | The report indicates that microsporidial spores are present, probably Enterocytozoon bieneusi or Encephalitozoon intestinalis or both; these tend to disseminate from the gastrointestinal tract to the kidneys; identification to the genus/species level is not possible from stained smears | Enterocytozoon bieneusi and Encephalitozoon intestinalis are the two most likely organisms present; these comments are very helpful, especially in indicating that the two organisms cannot be identified to the genus or species level on the basis of calcofluor white or modified-trichrome-stained smears |