title: How safe is safe: new human immunodeficiency virus Type 1 variants missed by nucleic acid testing.
abstract: BACKGROUND
  Nucleic acid amplification techniques (NAT) in routine blood donor screening considerably reduce the diagnostic window phase period. Nevertheless, several reports of false-negative NAT results were published. Here, four cases of human immunodeficiency virus Type 1 (HIV-1) RNA-positive blood donations that escaped detection by NAT screening are described.
  
  
  METHODS
  A total of 2.7 million blood donations were screened for viral infections between January 2010 and October 2012 in our German Red Cross blood donation service. Four plasma specimens with false-negative NAT results were comparatively investigated with 12 CE-marked NAT assays. In two cases of putative HIV-1 variants the target region of the NAT assay was sequenced allowing comparison with the respective primers and probes.
  
  
  RESULTS
  Most of the NAT assays used in routine blood donor screening with the 5'-long terminal repeat (LTR) as target region demonstrated deficiencies in detecting the viral variants and the low-viral-carrier donations. Sequence analysis revealed in one case a deletion of 56 nucleotides within the 5'-LTR preventing the binding of the probe accompanied by a neighbored insertion of another 52 nucleotides and several primer mismatches in another case. No false-negative results were obtained for these cases using dual-target assays. The viral load of the remaining two false-negative results was below the NAT's limit of detection.
  
  
  CONCLUSIONS
  HIV-1 is characterized by a high mutation rate and rapid generation of new viral variants. By the use of one target region for HIV-1 NAT assays there is a certain risk of false-negative results. Employing HIV-1 multi- and dual-target assays in routine blood donor screening seems to be a reasonable possibility to minimize this problem.
authors.affiliation: DRK Blutspendedienst West, Hagen, Germany; Paul-Ehrlich-Institut, Langen, Germany; GFE Blut mbH, Frankfurt am Main, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Müller
authors.forename: C Micha
authors.initials: CM
authors.lastname: Nübling
authors.forename: Julia
authors.initials: J
authors.lastname: Kress
authors.forename: W Kurt
authors.initials: WK
authors.lastname: Roth
authors.forename: Silke
authors.initials: S
authors.lastname: De Zolt
authors.forename: Lutz
authors.initials: L
authors.lastname: Pichl
mesh_terms: D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D001782:Blood Donors / Q000706:statistics & numerical data; D058731:Blood Safety / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D003951:Diagnostic Errors; D005188:False Negative Reactions; D005260:Female; D014644:Genetic Variation; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission; D015497:HIV-1 / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D008875:Middle Aged; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D012698:Serologic Tests / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data