Test Code LABBKV BK Virus, Molecular Detection and Quantitation, Plasma

Additional Codes

Test Name in EPIC	EPIC Test Code	Mnemonic
BK Virus, Molecular Detection and Quantitation, Plasma	LABBKV	BKV

Performing Laboratory

SMDC Clinical Laboratory

Specimen Type

Plasma EDTA

Specimen Required

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL (min 0.8mL)

Specimen Stability Information

Refrigerated: 5 days

Method and Method Description

Abbott Alinity m System by real-time polymerase chain reaction (PCR)

Alinity m BKV is an in vitro nucleic acid amplification test for the
quantitation of BK virus (BKV) DNA in human EDTA plasma (K2EDTA,
K3EDTA, and PPT) and urine stabilized using the Alinity m Urine
Transport Kit on the automated Alinity m System.
In EDTA plasma (K2EDTA, K3EDTA, and PPT) and urine stabilized using
the Alinity m Urine Transport Kit, Alinity m BKV is intended for use as an
aid in the diagnosis and management of BKV in transplant patients.
In patients undergoing monitoring of BKV in EDTA plasma, serial DNA
measurements can be used to indicate the need for potential treatment
changes and to assess viral response to treatment.
The results from Alinity m BKV must be interpreted in conjunction with
clinical signs and symptoms and other relevant laboratory findings.
Alinity m BKV is not cleared as a screening test for blood or blood
products or human cells, tissues, and cellular and tissue-based products.

Useful For/Utility

Detection and serial monitoring of BK virus-associated nephropathy in kidney transplant recipients using plasma specimens

Detection and serial monitoring of BK virus-associated hemorrhagic cystitis in organ transplant recipients

CPT(s)

87799

Reference Values

Not Detected

Day(s) Test Set Up

Monday through Friday

LOINC

Order LOINC 32284-2

Component LOINC

32362-6

32284-2

108224-7

Interpretation

The Alinity m System will report a Result and an Interpretation for each
plasma specimen.
The Lower Limit of Quantitation (LLoQ) for plasma specimens is
50 IU/mL (1.70 Log IU/mL). The Upper Limit of Quantitation (ULoQ) for
plasma specimens is 1,000,000,000 IU/mL (9.00 Log IU/mL).

Cautions

On average, quantitative BK virus (BKV) DNA results in plasma tested with this assay can be up to 1.4-fold (about 0.15 log IU/mL) higher than those generated from the previous laboratory-developed BKV DNA quantification assay performed at Mayo Clinic Laboratories, due to differences in the specimen extraction method and design in the amplification primers and probes for the viral target sequences.

A single "Undetected" test result does not necessarily rule out the presence BKV infection or reactivation. Serial measurement (eg, once weekly) of BKV DNA in plasma is recommended to determine the BKV replication status in a given transplant recipient.

Clinical Information

BK virus (BKV) is a circular, double-stranded DNA virus with an approximately 5 kilobase-size genome in the polyomavirus family, of which 13 members of the family are known, including the JC virus (JCV) and SV40. BKV shares about 75% of its DNA sequence with JCV. Nearly 80% of the adult population worldwide have antibodies to both viruses, indicating previous infection or exposure to these viruses.

Initial infection with BKV is usually acquired in childhood, mostly asymptomatic or manifesting as a mild flu-like illness. After primary infection, BKV establishes latency in the kidney and bladder of the infected individual. In the setting of immunosuppression, the virus reactivates and begins to replicate, triggering renal tubular cell lysis and viruria. As the reactivation progresses, the virus multiplies and crosses into the bloodstream, causing viremia and invading the kidney graft. In patients with kidney transplants, reactivation of BKV typically reaches peak incidence at 3 months posttransplantation with BK viral replication in the kidney graft, causing BKV-associated nephropathy (BKVAN), which manifests as kidney dysfunction that may result in eventual loss of the transplanted kidney. Reactivation of BKV in the bladder can lead to hemorrhagic cystitis. Currently, there are no US Food and Drug Administration-approved antiviral agents or treatments for BKVAN or BKV-associated hemorrhagic cystitis. The main treatment is to decrease the immunosuppression, with the risk of acute rejection of the kidney graft.

After BK reactivation, the virus is first detectable in the urine, with viremia developing several weeks later. Quantitative BKV DNA in the plasma is the most widely used and preferred test for the laboratory diagnosis of BKVAN and BKV-associated hemorrhagic cystitis, as BKV viremia has higher positive predictive value (50%-60%) than BKV viruria for the diagnosis of BKVAN. Serial monitoring of BKV DNA level in plasma is recommended to guide optimal immunosuppressant dosing regimen. In those with BKVAN, clearance of BK viremia is a sign of resolution of the nephropathy

Specimen Stability