Comparison of the Abbott Alinity m and Qiagen Artus assays for the quantification of BK virus in clinical samples.

Objectives: BK virus (BKV) is highly seroprevalent in humans. After primary infection, it remains latent in the urinary tract and can reactivate in immunocompromised individuals, leading to interstitial nephropathy or hemorrhagic cystitis. The BKV viral load (VL) in plasma correlates with the occurrence of nephropathy and can be monitored in kidney graft recipients; the early detection of BKV viremia can enable an early reduction of immunosuppressant drug doses and the prevention of BKV-associated nephropathy. BKV VL is measured using real-time reverse transcription-polymerase chain reaction. Our aim was to evaluate the Abbott Alinity m BKV AMPL kit versus the Artus BKV quantification kit (Qiagen, Hilden, Germany).

Methods: We compared the methods on 69 plasma samples, 54 urine samples, and 12 external quality control samples. To assess analytical sensitivity, serial dilutions of internal control were also tested.

Results: Specificity reached 100%. Fifty-seven of the 59 plasma samples were found to be positive (sensitivity: 96.6%), as were 46 of the 48 urine samples (sensitivity: 95.8%). In quantifiable samples, the VL was correlated with the findings on plasma (r = 0.965) and urine samples (r = 0.971). The mean differences were 0.78 log and 0.28 log in plasma and urine samples, respectively. A comparison of the BKV VL in external quality control samples produced a correlation coefficient of 0.930 and a mean difference of 0.07 log IU/ml. The calculated analytical sensitivity was 15 IU/ml with 95% probability.

Conclusions: The Alinity m BKV AMPL kit is compatible with diagnostic use and can be used in a "random-access" manner, thus reducing the time between sampling and the results being available to clinicians.