title: HIV RNA testing in the context of nonoccupational postexposure prophylaxis.
abstract: BACKGROUND
  The specificity and positive predictive value of human immunodeficiency virus (HIV) RNA assays have not been evaluated in the setting of postexposure prophylaxis (PEP).
  
  
  METHODS
  Plasma from subjects enrolled in a nonoccupational PEP study was tested with 2 branched-chain DNA (bDNA) assays, 2 polymerase chain reaction (PCR) assays, and a transcription-mediated amplification (TMA) assay. Assay specificity and positive predictive value were determined for subjects who remained negative for HIV antibody for >or=3 months.
  
  
  RESULTS
  In 329 subjects examined, the lowest specificities (90.1%-93.7%) were seen for bDNA testing performed in real time. The highest specificities were seen with batched bDNA version 3.0 (99.1%), standard PCR (99.4%), ultrasensitive PCR (100%), and TMA (99.6%) testing. Only the 2 assays with the highest specificities had positive predictive values >40%. For the bDNA assays, increasing the cutoff point at which a test is called positive (e.g., from 50 copies/mL to 500 copies/mL for version 3.0) increased both specificity and positive predictive values to 100%.
  
  
  CONCLUSIONS
  The positive predictive value of HIV RNA assays in individuals presenting for PEP is unacceptably low for bDNA-based testing and possibly acceptable for PCR- and TMA-based testing. Routine use of HIV RNA assays in such individuals is not recommended.
authors.affiliation: Positive Health Program at San Francisco General Hospital, Department of Medicine, University of California, San Francisco, CA 94110, USA. mroland@php.ucsf.edu
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Roland
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Elbeik
authors.forename: James O
authors.initials: JO
authors.lastname: Kahn
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Bamberger
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Coates
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Krone
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Katz
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Martin
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use; D021121:Branched DNA Signal Amplification Assay; D015658:HIV Infections / Q000175:diagnosis / Q000517:prevention & control*; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood*; D012680:Sensitivity and Specificity; D015229:Sexually Transmitted Diseases, Viral / Q000188:drug therapy / Q000517:prevention & control*; D015819:Substance Abuse, Intravenous / Q000150:complications*; D014158:Transcription, Genetic
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral