Posted Date
Effective Date
CPT Code 87799
Order Code QBKV
Referral Laboratory Mayo Medical Laboratories



BK Virus DNA by PCR, Quantitative, Plasma

Order Codes:                QBKV

Fee Code:                     LA019 (CPT 87799)


The Michigan Medicine Clinical Microbiology Laboratory has switched from a laboratory developed test to the FDA approved Roche Cobas BKV Assay effective January 3, 2024. This switch will align our testing with over 70 other accredited pathology laboratories in the United States and provides:

  • Improved standardization
  • Direct traceability to WHO International Standard
  • Ability to compare results to other laboratories for both lab proficiency and development of guidelines
  • Improved sensitivity
  • Smaller sample volume


The Cobas BKV test will be reported in International Units (IU/mL) instead of copies/mL. The absolute values are expected to shift in patients being serially tested as follows:

  • On average, the Cobas BKV test result is 2-fold lower (0.3 log10 lower) in IU/mL compared to the old test in copies/mL. For example, a result of 5,000 IU/mL (3.7 log10 IU/mL) would have been ~10,000 copies/mL (4 log10 copies/mL) on the previous test.
  • However, there is a tight linear relationship between the old and new assays and we observe very similar trends in serial patient results over time in both assays.


Values will be reported in IU/mL and log10 IU/mL and a conversion factor comment will be provided.