Entamoeba histolytica/dispar – Differentiation

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

*Uncontrolled print copy. Valid only on day of print: 01 May 2024.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Entamoeba histolytical EIA	General Test Requisition	Unpreserved faeces³	1.0 grams	Sterile container

Submission and Collection Notes

Indicated on the requisition if the patient has Eosinophilia, HIV, is immunocompromised, has a Critical illness or was admitted to ICU, or had a previous parasitic infection.

Under ‘Travel’ section, indicate if patient is a new immigrant or refugee or returned traveler. It is imperative that the foreign country be identified.

Submit within 24 hours of collection.

Limitations

This test cannot be performed on SAF preserved faeces (i.e. standard stool O/P collection containers)

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.

Special Instructions

Place specimen in a biohazard bag and seal. Specimens should be shipped as per Transportation of dangerous Goods Regulation. Transfer as soon as possible to the laboratory. If immediate transportation is not available, specimen must be refrigerated before submission or frozen if there is a delay of more than 72 hours.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Entamoeba histolytica testing is performed Monday to Friday.

Turnaround time is up to 3 days from receipt by the PHO Laboratory.

Test Methods

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 and causing amoebiasis.

Algorithm

An ELISA (Enzyme Linked Immunosorbent Assay) based fecal antigen test (EHistoII) is used as the standard reference method at PHO laboratories to differentiate the two species.

Note: ELISA will not be performed if the patient is being treated for an Entamoeba infection or on a test of cure specimen