West Nile virus (WNV) – serology

Alternative Names/Synonyms	Molecular detection of West Nile virus and/or IgG/IgM antibody response
Laboratory	Microbiology
Sub-section	Serology
Specimen Type	Serology: ○ Whole blood, Serum ○ CSF PCR: ○ EDTA blood, plasma or serum

Other Information

○ CSF serology is the preferred method of testing for WNV. If submitting CSF for serology, a paired serum specimen must also be submitted.
○ PCR is not a sensitive test. It may be considered if the specimen is collected within 5 days of neurological onset during active mosquito season

Specimen Requirements (Tube Type)

○ Clotted blood – vacutainer tubes
○ Plasma with non-heparin anticoagulant (lavender top)
○ CSF: sterile container

Collection Requirements

Whole blood/serum:
○ Decontaminate skin with 70% alcohol followed by iodine or chlorhexidine, collect at least 5 mL of blood.
CSF:
○ Decontaminate skin, collect at least 0.5 mL of CSF by lumbar puncture

Sample Stability

Refer to section Sample Processing / Delivery

Referral Laboratory

In-house PCR (Donor Testing only ) PHOL PCR for diagnostic purposes and serology

Routine Turnaround Time

○ ELISA: Up to 2 days during peak season, 5 days off-peak
○ PRNT: Up to 10 days
○ PCR: Up to 21 days (in house donor testing within 24 hours)

Laboratory Contact Information

416-586-4800 extension 4644

Approval Required

NO; except for PCR

Sample Processing / Delivery

○ Label specimen container. Place specimens in biohazard bag and seal.

○ Specimen should be transported to the UHN/SH Microbiology Laboratory at refrigeration temperature (2-8˚C) immediately after collection. Donor samples can be stored at room temperature (20-25 ˚C) for up to 24 hours.

○ The specimen will be referred to the Public Health Ontario Laboratory for testing. PHOL will refer specimens for PCR or PRNT to NML.
UHN/Sinai Laboratory will perform molecular testing on donors in-house.