BK Urine Analysis
BK: Urine Analysis is a molecular test that detects and quantifies the level of BK virus DNA in urine. It is a useful tool to monitor the risk of developing BK viral nephropathy (BKVAN) in renal transplant recipients, as well as those who have undergone hematopoietic stem cell or hematologic transplantation and are at risk for infection with the BK virus. BK nephropathy is a progressive kidney disorder that can lead to kidney failure in some cases.
Infection with the BK virus is widespread in the human population and typically causes no symptoms. However, it may reactivate in those who are immunocompromised, such as after kidney or bone marrow transplantation, and is associated with kidney and bladder disease in these patients. The severity of BK nephropathy correlates with the level of BK virus load in urine. Molecular diagnostic methods provide earlier and more accurate detection of BK virus reactivation than conventional immunohistochemical staining of kidney biopsy tissue, as well as avoiding false-negative results that can occur with biopsy sampling [15].
A negative result means the presence of BKV DNA below the detection limit of the assay. A positive result indicates the presence of BKV DNA at a higher concentration than the detection limit. Quantitative values are reported in IU/mL and log IU/mL units.
A Bland-Altman analysis of raw and diluted BK PCR products showed that the assay yielded more reproducible results when samples were diluted. In addition, results from the diluted assay were significantly closer to those from the raw assay than to those from a previous laboratory-developed BK PCR assay.