Parasites (Tissue and Other Body Fluids) – Microscopy

Conformément au Règlement de l’Ontario 671/92 de la Loi sur les services en français, les renseignements d’analyses de laboratoire liés à la présente page ne sont offerts qu’en anglais parce qu’ils sont de nature scientifique ou technique et destinés uniquement à l’usage des fournisseurs de soins de santé qualifiés et non aux membres du public.

Background
This page is intended for microscopy requests involving parasites in body fluids or tissues other than blood or enteric parasites, including when a specific organism is not suspected. Organisms marked with an asterisk (*) have their own organism-specific webpage that includes information about additional testing methods. If suspecting one of these organisms with an asterisk, refer to their dedicated webpage for additional method availability.

Body Fluid or Tissue	Organisms
Neurologic	Protozoa: Acanthamoeba,Balamuthia*, Entamoeba*, Naegleria*, Toxoplasma, Trypanosoma* Helminths: Alaria, Angiostrongylus,* Baylisascaris, Echinococcus*, Fasciola*, Gnathostoma, Halicephalobus, Lagochilascaris, Ophidascaris, Paragonimus, Schistosoma*, Spirometra, Strongyloides*, Taenia*, Trichinella, Toxocara, Versteria
Ocular	Protozoa: Acanthamoeba, Dictyostelium, Toxoplasma Helminths: Alaria, Angiostrongylus, Baylisascaris, Dirofilaria, Echinococcus, Fasciola, Gnathostoma, Lagochilascaris, Loa, Philophthalmus, Spirometra,* Strongyloides, Taenia, Thelazia, Toxocara, Trichinella, Versteria* Arthropods: Diptera
Respiratory	Protozoa: Balantioides, Entamoeba, Toxoplasma Helminths: Alaria, Angiostrongylus, Baylisascaris, Clinostomum, Echinococcus, Eucoleus, Gnathostoma, Lagochilascaris, Mammomonogamus, Ophidascaris, Paragonimus, Schistosoma, Spirometra, Strongyloides, Toxocara, Trichinella, Versteria Arthropods: Diptera, Pentastomida*
Musculoskeletal	Protozoa: Sarcocystis, Toxoplasma* Helminths: Alaria, Baylisascaris, Echinococcus, Fasciola, Gnathostoma, Haycocknema, Paragonimus, Spirometra,* Taenia, Trichinella, Toxocara*
Hepatic	Protozoa: Entamoeba, Leishmania Helminths: Alaria, Angiostrongylus, Baylisascaris, Calodium, Dicrocoelium, Echinococcus, Fasciola, Gnathostoma,* Paragonimus, Opisthorchidae (including Clonorchis*), Ophidascaris,* Schistosoma, Spirometra, Strongyloides, Toxocara, Versteria Arthropods: Pentastomida
Genitourinary	Protozoa: Balantioides, Entamoeba, Enterobius, Trichomonas Helminths: Dioctophyme, Echinococcus, Gnathostoma, Schistosoma, Spirometra, Strongyloides Arthropods: Diptera*
Mucocutaneous	Protozoa: Acanthamoeba, Balamuthia, Balantioides, Entamoeba, Leishmania, Trypanosoma* Helminths: Alaria, Ancylostomatidae, Dioctophyme, Dirofilaria, Dracunculus, Enterobius, Gnathostoma, Lagochilascaris, Loa, Mansonella, Oesophagostomum, Onchocerca, Paragonimus, Taenia, Ternidens, Schistosoma, Sparganum, Spirometra, Strongyloides Arthropods: Anoplura, Demodex, Diptera, Ixodidae, Tunga, Sarcoptes

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 19 oct. 2026.

Testing Indications

Microscopy may be indicated for the diagnosis of individuals suspected of a parasitic infection. In some instances, other testing methods such as PCR and/or antibody testing may be more appropriate. Refer to the table above for specific organisms with asterisks that have webpages with more information available on additional testing method.

The following information is mandatory for testing to be approved:

Specimens are only accepted if originating from human sources. Specimens submitted from animal (e.g. pets) or environmental (e.g. food) sources will be rejected.
Specimens received without any clinical or exposure information may result in rejection or testing delay.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Parasite - Microscopy	General Test Requisition	Body fluid or tissue specimens (e.g., CSF, scrapings, biopsies, aspirates, sputum, BAL, brushings, urine)	1.0 ml (fluid) or 0.2 mg (tissue)	Empty sterile container

Submission and Collection Notes

Complete all fields of the requisition form.

Important: Specify which organism(s) are suspected on the requisition, if known.

Important: Provide complete clinical and exposure information on the requisition.

For tissue biopsies: if the collection vial used does not already contain sterile normal (0.85%) saline or PBS, add a small amount (≤ 0.5 ml) to keep the sample hydrated during transport.

Label the specimen container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay.

If the patient is part of a cluster/outbreak investigation, contact PHO Laboratory Customer Service at 416-235-6556/1-877-604-4567 prior to sample submission.

Storage and Transport

Place specimen container in a biohazard bag and properly seal the bag. Specimens should be stored at 2-8°C and shipped to PHO on ice packs within 48 hours of collection. All specimens must be shipped in accordance with the Transportation of Dangerous Good Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Parasite microscopy is performed daily from Monday to Saturday at PHO’s Toronto site. Turnaround time is up to 7 calendar days from receipt at PHO.

STAT and Critical Specimens Testing

If Strongyloides hyperinfection or disseminated disease is suspected, submit specimens for urgent testing as per below:

Notify PHO before sending a priority specimen by contacting our Customer Service Centre at 416-235-6556, 1-877-604-4567, or customerservicecentre@oahpp.ca.
Ship urgent specimens separately from routine specimens in a clearly marked package (in accordance with the Transportation of Dangerous Goods Regulations) indicating “Priority” for easier retrieval.
Clearly mark as “Urgent” with the appropriate suspected organism (Strongyloides) on the requisition.
Ship priority specimens directly to PHO’s Toronto laboratory site to the shipping and receiving dock at 661 University Ave., Toronto, Ontario. For delivery instructions please see Directions to 661 University Shipping Dock for Clinical Samples.

Priority specimens will be tested and resulted within 1 calendar day. Failure to follow the submission instructions above may result in testing delays.

Test Methods

Parasite microscopy is performed at PHO using a combination of Giemsa staining, acid-fast staining, and sedimentation concentration.

Performance and Limitations:
Microscopy accuracy varies significantly by organism type, specimen type, intensity of infection, and time from exposure (i.e. prepatent period). In some instances, other testing methods such as PCR and/or serology may be more accurate (see listing above for details).

Interpretation

Microscopy:

Parasite microscopy	Interpretation
Parasite(s) found	Evidence of parasitic organism(s). The organism name(s) and stage(s) will be reported.
No parasites found	No evidence of parasitic organism(s). Does not rule out infection. In some instances, other testing methods such as PCR and/or serology may be more appropriate (see PHO test menu).

Reporting

Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

In addition, Entamoeba histolytica and Trichinella positive results are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.