BK viral load, BK virus by PCR, BK virus DNA quant, BKV by PCR, BKV DNA quant, BKV viral load
Detection and serial monitoring of BK virus- (BKV) associated nephropathy in kidney transplant recipients using random urine specimens
Detection and serial monitoring of BKV-associated hemorrhagic cystitis in organ transplant recipients
This assay detects and quantifies the level of BK virus (BKV) DNA present in the urine of kidney transplant recipients who are at risk of developing BKV-associated nephropathy or hemorrhagic cystitis leading to decreasing renal function and eventual renal failure. The assay is calibrated to the First World Health Organization International Standard for BKV DNA.
1. Collect a random urine into a sterile, plastic, preservative-free container.
2. Transfer 4.3 mL of urine into the cobas PCR urine sample tube using the disposable pipette provided within 24 hours of collection. The correct volume of urine has been added when the fluid level is between the black fill lines on the urine transport tube. Place the labels on the transport tube so the black fill lines are still visible for volume confirmation at Mayo Clinic Laboratories.
3. Transport and store urine specimen transport container at 2 to 30 degrees C (refrigerate is preferred temperature).
Additional Information: cobas PCR media contains guanidine hydrochloride. Do not allow these tubes to come in direct contact with sodium hypochlorite (bleach) or other highly reactive reagents such as acids and bases. These mixtures can release a noxious gas.
ON AVERAGE, QUANTITATIVE BK VIRUS (BKV) DNA RESULTS IN URINE TESTED WITH THIS ASSAY CAN BE UP TO 3.5-FOLD (ABOUT 0.54 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 urine or plasma is recommended to determine the BKV replication status in a given transplant recipient.
While unlikely to be present in urine specimens, vaginal lubricants, speculum jellies, creams, and gels containing carbomers may interfere with the test and should not be used during or prior to sample collection. Urogenital specimens from patients who have used carbomer-containing products such as Replens Long-Lasting Vaginal Moisturizer, RepHresh Odor Eliminating Vaginal Gel and RepHresh Clean Balance or used metronidazole vaginal gel may generate invalid or false-negative results.
The quantification range of this assay is 200 to 100,000,000 IU/mL (2.30 log to 8.00 log IU/mL), with a limit of detection (95% detection rate) at 12 IU/mL.
An "Undetected" test result indicates the absence of BK virus (BKV) DNA in the urine.
A test result of "<200 IU/mL (<2.30 log IU/mL)" indicates that BKV DNA is detected in the urine, but the assay cannot accurately quantify the BKV DNA present below this level.
A quantitative value (reported in IU/mL and log IU/mL) indicates the level of BKV DNA (ie, viral load) present in the urine.
A test result of ">100,000,000 IU/mL (>8.00 log IU/mL)" indicates that BKV DNA level present in urine is above 100,000,000 IU/mL (8.00 log IU/mL), and the assay cannot accurately quantify BKV DNA present above this level.
AN "INCONCLUSIVE" RESULT INDICATES THAT THE PRESENCE OR ABSENCE OF BKV DNA IN THE URINE SPECIMEN COULD NOT BE DETERMINED WITH CERTAINTY AFTER REPEAT TESTING IN THE LABORATORY, POSSIBLY DUE TO POLYMERASE CHAIN REACTION INHIBITION OR PRESENCE OF INTERFERING SUBSTANCE. SUBMISSION OF A NEW SPECIMEN FOR TESTING IS RECOMMENDED IF CLINICALLY INDICATED.