Filaria – Microscopy

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.

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit


Unstained blood slides3


Slide mailer for unstained slides


EDTA blood

2.0 ml

EDTA blood tube

Submission and Collection Notes


Please note on the requisition (under other) if the patient has fever, intravascular hemolysis, hemoglobinuria, renal failure or is immunocompromised.


Indicate Country/Region and if the patient is a new immigrant or refugee or returned traveler under ‘Travel’ section of the requisition.


Submit unstained thick and thin slides AND EDTA blood. EDTA blood is required for Knott’s Concentration Procedure.

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 slide mailer in a biohazard bag and seal. Ship to the PHO laboratory as soon as possible.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Filaria testing is performed Monday to Friday.

Turnaround time is up to 2 days after receipt by PHO laboratory.

Test Methods

EDTA blood samples are examined for microfilaria using microscopy using the Knott’s Concentration Procedure.

Thick and thin smears are stained with Giemsa and examined by microscopy.


Results are reported to the ordering physician or health care provider as indicated on the requisition.

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Laboratory Services

Updated 20 July 2020