BK Virus

Testing Indications

Specimens for BK virus testing are referred to the National Microbiology Laboratory (NML) in Winnipeg.

NML provides confirmatory and reference molecular testing for equivocal results or diagnostic complexities following renal transplant.

Specimens for routine monitoring of transplant patients will not be accepted unless part of pre-arranged collaborative study.

Specimen Collection and Handling

Specimen Requirements

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

BK Virus


1.0 ml

Plasma preparation tube (PPT) or EDTA (plastic; lavender or pink top)

BK Virus


10 ml

Sterile collection container

BK Virus

Fresh biopsies


Sterile container

BK Virus

Fixed tissue

Sterile container

Submission and Collection Notes


If plasma is collected in PPT or EDTA, centrifuge tube at room temperature at 1,100RCF for 10-15 minutes. Aliquot plasma into separate plastic tube.


Indicate if the patient has had a bone marrow or renal transplant, is immunocompromised or has symptoms of ureteral stenosis or haemorrhagic cystitis on the General Test Requisition Form.

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. Plasma (collected in PPT or EDTA) or urine may be stored and shipped refrigerated within 48h of sample collection or must be stored and shipped frozen. Fresh biopsies must be stored frozen at all times and shipped on dry ice. Fixed tissue may be stored and shipped at room temperature.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Specimens for BK Virus testing are referred to the National Microbiology Laboratory (NML) in Winnipeg.

Turnaround time for virus culture is up to 14 days from receipt by PHO laboratory.

STAT and Critical Samples Testing

STAT samples may be considered under special circumstances. Please contact the Public Health Ontario laboratory to inquire about shorter turnaround time.


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

Test Methods

BK Virus specimens are tested by PCR at NML.

Urines can be tested by EM at PHOL, but this has very low sensitivity. For more information please refer to NML Pathogen Guide.

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Laboratory Services


Updated 20 July 2020