title: Validation for clinical use of a novel HIV-2 plasma RNA viral load assay using the Abbott m2000 platform.
abstract: BACKGROUND
  Optimal care of persons infected with human immunodeficiency virus type 2 (HIV-2) requires an accurate assessment of HIV-2 plasma viral load (VL), but no clinically approved quantitative HIV-2 RNA VL assay exists.
  
  
  OBJECTIVE
  To validate a novel quantitative HIV-2 RNA assay for clinical and research use.
  
  
  METHODS
  The Abbott m2000sp/rt platform was adapted for quantification of HIV-2 RNA in plasma. Amplification targeted a region of the long terminal repeat conserved in Group A and B HIV-2. Electron microscopy-counted-HIV-2 standards, the WHO/NIBSC HIV-2 International Standard and clinical specimens (N=162) were used to determine the precision, sensitivity, specificity, linear range, accuracy, and clinical performance of the assay.
  
  
  RESULTS
  The quantitative linear range of the HIV-2 RNA assay was 10-1,000,000 copies/mL (R(2)>0.99), with a limit of detection of 8 copies/mL (95% CI, 5-18 copies/mL). The assay did not cross-react with HIV-1, and quantification of HIV-2 RNA was not affected by the presence of >5 log(10)HIV-1 RNA copies/mL. The total standard deviation (SD) and intra- and inter-run SD were 0.095, 0.093 and 0.162, respectively, at nominal inputs of 3.7, 1.7 and 1.0 log(10)HIV-2 RNA copies/mL. The HIV-2 WHO/NIBSC International Standard (1000 IU) was shown to contain 152 RNA copies/mL (95% CI 141-163). Overall, HIV-2 RNA was quantified at ≥10 copies/mL from 86 (53%) clinical specimens (median, 2.24 log(10) copies/mL; range 10-16,870), and nine specimens (6%) had HIV-2 RNA detected at <10 copies/mL.
  
  
  CONCLUSIONS
  We developed and validated a highly sensitive HIV-2 VL assay that is suitable for clinical and research use.
authors: Department of Laboratory Medicine, Division of Virology, University of Washington, Seattle, United States.
authors: Ming
authors: M
authors: Chang
authors: Geoffrey S
authors: GS
authors: Gottlieb
authors: Joan A
authors: JA
authors: Dragavon
authors: Stephen L
authors: SL
authors: Cherne
authors: Donna L
authors: DL
authors: Kenney
authors: Stephen E
authors: SE
authors: Hawes
authors: Robert A
authors: RA
authors: Smith
authors: Nancy B
authors: NB
authors: Kiviat
authors: Papa Salif
authors: PS
authors: Sow
authors: Robert W
authors: RW
authors: Coombs
mesh_terms: D015658:HIV Infections / Q000821:virology*; D015498:HIV-2 / Q000302:isolation & purification*; D006801:Humans; D010949:Plasma / Q000821:virology*; D012367:RNA, Viral / Q000097:blood*; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods*
chemical_list: D012367:RNA, Viral