title: Identification of early HIV infections using the fourth generation Abbott ARCHITECT HIV Ag/Ab Combo chemiluminescent microparticle immunoassay (CIA) in San Diego County.
abstract: BACKGROUND
  HIV screening assays have gone through several generations of development in an effort to narrow the "window period" of detection. Utilizing a fourth generation HIV screening assay has the potential to detect earlier HIV infection, thus reducing HIV-1 transmission.
  
  
  OBJECTIVE
  To identify acute infections to decrease HIV transmission in San Diego County.
  
  
  METHODS
  Serum specimens were collected from clients seen by multiple submitters in San Diego County. All acceptable specimens were screened using the 4th Gen Combo Assay. Initially reactive specimens were repeated in duplicate and if repeatedly reactive, were confirmed by HIV-1 Immunofluorescent Antibody Assay (IFA). IFA negative/inconclusive specimens were sent for HIV-1 NAT and HIV-2 antibody testing to referral laboratories. BioRad Multispot HIV-1/HIV-2 Rapid Test was also performed on a subset of specimens.
  
  
  RESULTS
  Of 14,559 specimens received in 20 months, 14,517 specimens were tested. Of the 14,517 specimens that were tested, a total of 279 (1.9%) specimens were CIA repeatedly reactive and 240 of the 279 confirmed by HIV-1 IFA. Thirty-nine gave IFA negative/inconclusive result and 30 were further tested for HIV-1 NAT and 36 for HIV-2 antibody. Thirteen specimens were considered false positives by CIA and 17 specimens were classified as acute infections. Eleven of 39 IFA negative/inconclusive specimens were further tested by Multispot. Five of the 11 were positive by Multispot.
  
  
  CONCLUSIONS
  The fourth generation Abbott ARCHITECT HIV Ag/Ab Combo Assay identified 17 patients who may have been missed by the prior HIV-1 screening assay used at San Diego County Public Health Laboratory.
authors.affiliation: San Diego County Public Health Laboratory, 3851 Rosecrans Street, Suite 716, San Diego, CA 92110, United States. Electronic address: annaliza.manlutac@sdcounty.ca.gov.
authors.forename: Anna Liza M
authors.initials: AL
authors.lastname: Manlutac
authors.affiliation: San Diego County Public Health Laboratory, 3851 Rosecrans Street, Suite 716, San Diego, CA 92110, United States.
authors.forename: Jill S
authors.initials: JS
authors.lastname: Giesick
authors.affiliation: San Diego County Public Health Laboratory, 3851 Rosecrans Street, Suite 716, San Diego, CA 92110, United States.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: McVay
mesh_terms: D000465:Algorithms; D002140:California; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005455:Fluorescent Antibody Technique / Q000379:methods; D015483:HIV Antibodies / Q000097:blood*; D015488:HIV Antigens / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000276:immunology; D015498:HIV-2 / Q000145:classification* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D012367:RNA, Viral / Q000097:blood*; D014773:Virology / Q000379:methods
chemical_list: D015483:HIV Antibodies; D015488:HIV Antigens; D012367:RNA, Viral
keywords: 4th generation screening assay; Acute HIV infection; HIV RNA NAT; HIV antibodies; HIV-1 p24 antigen; Multispot Rapid Test