Powassan Virus

Specimen Collection and Handling

Specimen Requirements

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

Powassan virus serology

Blood or serum

5.0 ml blood or 1.0 ml serum

Vacutainer tubes (SST)

Powassan virus PCR

Plasma or serum

1.0 ml

EDTA blood, plasma with non-heparin anticoagulant

Powassan virus PCR

CSF (must be preapproved by PHOL microbiologist)

400 µl

Sterile container

Submission and Collection Notes


Molecular testing must must be preapproved by the PHO laboratory microbiologist. Contact PHO laboratory Customer Service at 416-235-6556 or 1877-604-4567 to request approval.


Complete the following on the General Test Requisition Form:

  • relevant travel history
  • onset date 
  • symptoms

Instructions for using SST tubes are found in the document titled: LAB-SD-008, Blood Collection using Serum Separator Tubes


Haemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.

Preparation Prior to 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 biohazard bag and seal. Specimens should be stored at 2-8◦C following collection and shipped to the PHO laboratory on ice packs.

Specimens for molecular testing should be frozen and shipped on dry ice.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Serology is performed at PHO laboratory. 

Turnaround time is up to 8 days from receipt by PHO laboratory.

Molecular testing is performed National Microbiology Laboratory after approval by the PHO laboratory microbiologist.

Turnaround time is up to 28 days from receipt by PHO laboratory.


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

Positive results from patients with encephalitis are also reported to the Medical Officer of Health as per Health Protection and Promotion Act.

Test Methods

Serology is performed using a Hemagglutination Inhibition Assay for the detection of antibodies to Powassan Virus.

Molecular testing by RT-PCR is performed at the National Microbiology Laboratory after approval by the PHO laboratory microbiologist.

Mis à jour le 20 juill. 2020