title: Polyomavirus polymerase chain reaction as a surrogate marker of polyomavirus-associated nephropathy.
abstract: BACKGROUND
  Polyomavirus-associated nephropathy (PVAN) is a significant cause of allograft loss after renal transplantation. A noninvasive assay that can guide the evaluation of PVAN would be of clinical value. We compared the utility of BK virus (BKV) polymerase chain reaction (PCR) and urine cytology in screening for concurrent PVAN.
  
  
  METHODS
  We used PCR to test urine and plasma samples from renal recipients simultaneously for BKV DNA. Additionally, we tested urine samples for decoy cells. Sample results were correlated with biopsy-proven PVAN. Receiver-operator characteristic curves were used to determine viral load thresholds associated with concurrent PVAN.
  
  
  RESULTS
  In this cross-sectional study, BKV viruria, viremia, and urinary decoy cells were detected in 24%, 9%, and 13% of renal recipients, respectively. Among 114 patients who had renal allograft biopsy, four (3.5%) were diagnosed with PVAN. Using pathology as gold standard for the diagnosis of PVAN, BKV viremia threshold of >1.6E+04 copies/mL had 100% sensitivity, 96% specificity, 50% positive predictive value, and 100% negative predictive value. A BKV viruria threshold of >2.5E+07 copies/mL had 100% sensitivity, 92% specificity, 31% positive predictive value, and 100% negative predictive value. In contrast, urine decoy cells had 25% sensitivity, 84% specificity, 5% positive predictive value, and 97% negative predictive value for the diagnosis of concurrent PVAN.
  
  
  CONCLUSIONS
  BKV PCR may be a clinically useful noninvasive test to identify renal recipients with concurrent PVAN. BKV DNA >1.6E+04 copies/mL of plasma and >2.5E+07 copies/mL of urine were highly associated with concurrent PVAN whereas a negative PCR test makes the diagnosis of PVAN highly unlikely.
authors: Division of Clinical Microbiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors: Helen B
authors: HB
authors: Viscount
authors: Albert J
authors: AJ
authors: Eid
authors: Mark J
authors: MJ
authors: Espy
authors: Matthew D
authors: MD
authors: Griffin
authors: Kristine M
authors: KM
authors: Thomsen
authors: William S
authors: WS
authors: Harmsen
authors: Raymund R
authors: RR
authors: Razonable
authors: Thomas F
authors: TF
authors: Smith
mesh_terms: D000328:Adult; D000368:Aged; D001739:BK Virus / Q000235:genetics* / Q000472:pathogenicity; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001706:Biopsy; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000097:blood / Q000235:genetics / Q000652:urine; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology / Q000821:virology; D007674:Kidney Diseases / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D027601:Polyomavirus Infections / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014412:Tumor Virus Infections / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D019562:Viral Load
chemical_list: D015415:Biomarkers; D004279:DNA, Viral