title: Sequence Variation in Amplification Target Genes and Standards Influences Interlaboratory Comparison of BK Virus DNA Load Measurement.
abstract: International guidelines define a BK virus (BKV) load of ≥4 log10 copies/ml as presumptive of BKV-associated nephropathy (BKVN) and a cutoff for therapeutic intervention. To investigate whether BKV DNA loads (BKVL) are comparable between laboratories, 2 panels of 15 and 8 clinical specimens (urine, whole blood, and plasma) harboring different BKV genotypes were distributed to 20 and 27 French hospital centers in 2013 and 2014, respectively. Although 68% of the reported results fell within the acceptable range of the expected result ±0.5 log10, the interlaboratory variation ranged from 1.32 to 5.55 log10. Polymorphisms specific to BKV genotypes II and IV, namely, the number and position of mutations in amplification target genes and/or deletion in standards, arose as major sources of interlaboratory disagreements. The diversity of DNA purification methods also contributed to the interlaboratory variability, in particular for urine samples. Our data strongly suggest that (i) commercial external quality controls for BKVL assessment should include all major BKV genotypes to allow a correct evaluation of BKV assays, and (ii) the BKV sequence of commercial standards should be provided to users to verify the absence of mismatches with the primers and probes of their BKV assays. Finally, the optimization of primer and probe design and standardization of DNA extraction methods may substantially decrease interlaboratory variability and allow interinstitutional studies to define a universal cutoff for presumptive BKVN and, ultimately, ensure adequate patient care.
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Solis
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Mariam
authors.initials: M
authors.lastname: Meddeb
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Sueur
authors.affiliation: Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Pilar
authors.initials: P
authors.lastname: Domingo-Calap
authors.affiliation: Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Soulier
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Angeline
authors.initials: A
authors.lastname: Chabaud
authors.affiliation: Département de Néphrologie-Transplantation, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Peggy
authors.initials: P
authors.lastname: Perrin
authors.affiliation: Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France Département de Néphrologie-Transplantation, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Moulin
authors.affiliation: Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Seiamak
authors.initials: S
authors.lastname: Bahram
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Stoll-Keller
authors.affiliation: Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France Département de Néphrologie-Transplantation, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Caillard
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.
authors.forename: Heidi
authors.initials: H
authors.lastname: Barth
authors.affiliation: Laboratoire de Virologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France samira.fafi-kremer@unistra.fr.
authors.forename: Samira
authors.initials: S
authors.lastname: Fafi-Kremer
mesh_terms: D001739:BK Virus / Q000235:genetics* / Q000302:isolation & purification*; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D005602:France; D014644:Genetic Variation; D006761:Hospitals; D006801:Humans; D059021:Laboratory Proficiency Testing; D027601:Polyomavirus Infections / Q000175:diagnosis* / Q000821:virology; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods* / Q000592:standards*
chemical_list: D004279:DNA, Viral