A rapid immunochromatographic assay for the detection of BK Polyomavirus in urine samples from hematopoietic stem cell transplant recipients

Hemorrhagic cystitis (HC) following hematopoietic stem cell transplantation (HSCT) is a significant event that can lengthen hospital stays and the need for care. The causes of HC can be multiple, but BK Polyomavirus (BKPyV) is the main protagonist in frequency. Currently, the clinical tool widely used to detect the presence of the virus in urine is PCR-based viral genome testing. We have developed a new rapid test for the antigenic detection of BKPyV in urine. The aim of this diagnostic study was to retrospectively evaluate the performance of this new assay as compared to BKPyV PCR on urine from HSCT patients with suspected HC. 49 samples from 49 different patients were evaluated, 20 of whom presented with HC. Of these 20 samples, 19 (95 %) were positive by the rapid antigen test. Of the 37 BKPyV PCR-positive samples, 31 were above 7 log₁₀ copies/mL, including the 20 patients with HC. Thus, the overall performance of the rapid test for HC is greatly improved compared with PCR, with specificity rising from 62.1 % to 86.2 % and positive predictive value from 64.5 % to 82.6 %. In conclusion, this new tool could be implemented as a point-of-care test to rapidly confirm or rule out a suspicion of BKPyV-HC after HSCT.