4-7 ml; for infants a volume of 2-4 ml is acceptable
4 ml; for infants a volume of 2 ml is acceptable
Keep specimen at 4C
When monitoring the blood of immunocompromised patients for BK virus over time, a quantitative PCR assay will be automatically performed on all patients whose blood has been previously positive for BK virus by qualitative and/or quantitative PCR testing.
Amplification and detection of BK virus DNA using real-time TaqMan PCR and nucleic acid primer/probe pairs specific for conserved regions of the BK virus genome. This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
BK virus can cause ureteral ulcerations, stenosis, and hemorrhagic cystitis in renal transplant recipients. Persistent active replication of BKV in renal transplant recipients also has been associated with progressive loss of the graft due to BKV-associated nephropathy. BKV-associated hemorrhagic cystitis is a major complication of bone marrow transplants. Continuous monitoring of urine and plasma by real-time PCR is desirable to predict disease and follow recovery over time.
If positive, the quantity of BK virus DNA is reported in both copies/ml and log10 values. Dynamic range of the assay is 302 copies/ml to 600 million copies/ml or 2.48 log10 copies/ml to 8.79 log10 copies/ml.
Negative or quantity of BK virus DNA is less than the lower limit of detection
Quantitative viral load results are best reflected when reported using log transformed units of copies/ml of nucleic acid. Logarithmic expression best reflects the process of viral replication and is less subject to over-interpretation of minor (non-clinically significant) changes. For this reason, all viral load results are reported not only as copies/ml but log10 copies/ml of nucleic acid.