Entamoeba histolytica – Faeces-Para
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Ova and Parasites
Faeces / Stool3,4,5
Submission and Collection Notes
Please note on the requisition (under other): If the patient has Eosinophilia, HIV, is immunocompromised, has a Critical illness or was admitted to ICU, or had a previous parasitic infection.
Indicate Country/Region and if the patient is a new immigrant or refugee or returned traveler under ‘Travel’ section of the requisition.
Collect a sample in each white top and yellow top (SAF) vial of the Parasitology Kit. Follow the collection instructions on the instruction sheet provided with the Parasitology Kit.
Collect one specimen per day for 3 days in each vial for a total of six (6) specimens.
The submission of the white top vial will allow for method development of newer and more sensitive methods such as enzyme immunoassay (EIA) and polymerase chain reaction (PCR) to obtain improved species identification.
Anti-diarrhoeal medication, radiological dyes (barium) and antibiotics interfere with the identification of intestinal protozoa, helminths, and coccidians.
Storage and Transport
Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.
Place specimen container in a biohazard bag and seal. Reminder: Store the yellow capped container at room temperature at all times. The white capped container must be refrigerated before submission or frozen if there is a delay of more than 72 hours.
Follow the instruction found in the updated Para Kit Instruction Sheet.
Collect faeces in clean dry container and immediately transfer a portion of the sample to the:
- White Cap sterile container and then emulsify another portion in the
- SAF preservative in the Yellow top container (Mix 1 part faeces with 3 parts SAF or 1 part liquid faeces with 1 part SAF).
The submission of the white top container will allow for method development of newer and more sensitive methods such as polymerase chain reaction (PCR) to obtain improved species identification.
Test Frequency and Turnaround Time (TAT)
Entamoeba histolytica testing is performed Monday to Friday.
Turnaround time is up to 5 days from receipt by the PHO laboratory.
Entamoeba histolytica specimens are examined by microscopy by preparing a smear and concentrate following a centrifugation procedure using the Formalin/Ethyl-acetate method. The concentration method allows for detection of small numbers of organisms.
It has been established that Entamoeba histolytica is morphologically identical to the non-pathogenic protozoan Entamoeba dispar.
Only Entamoeba histolytica is capable of tissue invasion ad causing amoebiasis.
An ELISA based fecal antigen test is used as the standard reference method at PHO laboratories to differentiate the two species.
NB: ELISA will only be performed following a positive microscopy for E. histolytica on an SAF preserved specimen. The test will not be performed if the patient is being treated for an Entamoeba infection or on a test of cure specimen. See document titled: LAB-SD-013 Entamoeba histolytica/dispar Differentiation test.
Results are reported to the ordering physician or health care provider as indicated on the requisition.
A “Note to Physicians” is attached to positive specimens that contain Entamoeba histolytica/dispar requesting the submission of a specimen in a sterile, dry clean container for molecular testing.