The Noninvasive Urinary Polyomavirus Haufen Test Predicts BK Virus Nephropathy in Children After Hematopoietic Cell Transplantation: A Pilot Study

After hematopoietic cell transplantation (HCT), polyoma-BK virus is associated with hemorrhagic cystitis and also with polyomavirus nephropathy (PVN). However, the true burden of post-HCT PVN is unknown because kidney biopsies are avoided due to their bleeding risk. The novel, non-invasive urinary PV-Haufen test detects PVN in kidney transplant recipients with >95% positive/negative predictive values. We hypothesized that the detection of PV-Haufen in voided urine samples–a positive PV-Haufen test–was also clinically significant after HCT