title: Reduced frequency of blood donors with false-positive HIV-1 and -2 antibody EIA reactivity after elution of low-affinity nonspecific natural antibodies.
abstract: BACKGROUND
  The detection by EIA of antibodies (Abs) specific to HIV antigens in the serum of blood donors is important for transfusion safety. A small but significant number of donor sera (0.1-0.3%) yield false-positive results in EIA, and these donors must be permanently deferred from the blood donor list, causing operational and public relations problems.
  
  
  METHODS
  False-positive EIA reactions could be caused by the binding of low-affinity natural polyreactive Abs, which could be eluted by treatment with a chaotropic agent such as thiocyanate (SCN). The effect of the SCN elution on EIA specificity was studied using tetanus toxoid and HIV Abs.
  
  
  RESULTS
  SCN elution preferentially reduced the binding of nonspecific Abs. Testing of 235 seronegative samples in HIV-1 and -2 EIA showed that SCN elution reduced the mean and dispersion of OD values obtained. In addition, SCN elution abolished the false-positive reactivity in HIV-1 and -2 EIA of 69 percent (299/435) of the repeatedly reactive specimens tested without impact on the reactivity of HIV-seropositive specimens.
  
  
  CONCLUSIONS
  The SCN elution step increased the specificity of HIV-1 and -2 EIA and could facilitate the re-entry of previously deferred donors.
authors.affiliation: HEMA-QUEBEC, R&D Department, Sainte-Foy, Canada.
authors.forename: Marlene
authors.initials: M
authors.lastname: Bouillon
authors.forename: Eric
authors.initials: E
authors.lastname: Aubin
authors.forename: Chantal
authors.initials: C
authors.lastname: Roberge
authors.forename: Renée
authors.initials: R
authors.lastname: Bazin
authors.forename: Réal
authors.initials: R
authors.lastname: Lemieux
mesh_terms: D001782:Blood Donors; D005189:False Positive Reactions; D015483:HIV Antibodies / Q000032:analysis*; D015497:HIV-1 / Q000276:immunology*; D015498:HIV-2 / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D013745:Tetanus Toxoid; D013861:Thiocyanates
chemical_list: D015483:HIV Antibodies; D013745:Tetanus Toxoid; D013861:Thiocyanates; C031760:thiocyanate