title: Evaluation of a BK virus viral load assay using the QIAGEN Artus BK Virus RG PCR test.
abstract: BACKGROUND
  Viral load testing for BK Virus (BKV) has become the standard of care for the diagnosis of infection and monitoring of therapy of kidney transplant patients infected with BKV. However, there are currently no FDA-approved BKV quantification assays and no standardization among available tests.
  
  
  OBJECTIVE
  This study evaluated the performance of the Artus BK Virus RG PCR (RUO) assay (QIAGEN) for accuracy, linearity, precision, analytical sensitivity, specificity, and correlation with a referral laboratory test in patient samples.
  
  
  RESULTS
  Linear regression analysis of the quantitative results demonstrated a linear range of quantification from 192 to 194 million (2.28 to 8.29 log(10)) DNA copies/mL and a coefficient of determination (R(2)) of 0.994. A dilution series demonstrated a limit of detection and a limit of quantification of 2.00 log(10), and 2.30 log(10) copies/mL (>95% positivity rate), respectively. The precision of the assay was highly reproducible among runs with coefficients of variance (CV) ranging from 0.2% to 7.0%. A comparison of 34 matched samples showed a good agreement (R(2)=0.983) between the Artus BK test and the referral laboratory results, with an average positive bias (0.39 log(10) copies/mL). Genotyping analysis using large-T antigen sequences demonstrated that 90% of the positive samples were BKV type I, and that there was no significant difference in quantification between the referral laboratory and Artus BK Virus tests.
  
  
  CONCLUSIONS
  The Artus BK Virus RG PCR test is a reliable and sensitive assay for BKV DNA quantification as compared to the referral laboratory test.
authors.affiliation: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA. har2006@med.cornell.edu
authors.forename: Hanna
authors.initials: H
authors.lastname: Rennert
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Jenkins
authors.forename: Carmen
authors.initials: C
authors.lastname: Azurin
authors.forename: John
authors.initials: J
authors.lastname: Sipley
mesh_terms: D001739:BK Virus / Q000235:genetics* / Q000302:isolation & purification*; D016903:Drug Monitoring / Q000379:methods; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects; D016133:Polymerase Chain Reaction / Q000379:methods*; D027601:Polyomavirus Infections / Q000175:diagnosis / Q000821:virology; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods*