title: Evaluation of the CDC proposed laboratory HIV testing algorithm among men who have sex with men (MSM) from five US metropolitan statistical areas using specimens collected in 2011.
abstract: BACKGROUND
  Until recently most testing algorithms in the United States (US) utilized Western blot (WB) as the supplemental test. CDC has proposed an algorithm for HIV diagnosis which includes an initial screen with a Combo Antigen/Antibody 4th generation-immunoassay (IA), followed by an HIV-1/2 discriminatory IA of initially reactive-IA specimens. Discordant results in the proposed algorithm are resolved by nucleic acid-amplification testing (NAAT).
  
  
  OBJECTIVE
  Evaluate the results obtained with the CDC proposed laboratory-based algorithm using specimens from men who have sex with men (MSM) obtained in five metropolitan statistical areas (MSAs).
  
  
  METHODS
  Specimens from 992 MSM from five MSAs participating in the CDC's National HIV Behavioral Surveillance System in 2011 were tested at local facilities and CDC. The five MSAs utilized algorithms of various screening assays and specimen types, and WB as the supplemental test. At the CDC, serum/plasma specimens were screened with 4th generation-IA and the Multispot HIV-1/HIV-2 discriminatory assay was used as the supplemental test. NAAT was used to resolve discordant results and to further identify acute HIV infections from all screened-non-reactive missed by the proposed algorithm. Performance of the proposed algorithm was compared to site-specific WB-based algorithms.
  
  
  RESULTS
  The proposed algorithm detected 254 infections. The WB-based algorithms detected 19 fewer infections; 4 by oral fluid (OF) rapid testing and 15 by WB supplemental testing (12 OF and 3 blood). One acute infection was identified by NAAT from all screened-non-reactive specimens.
  
  
  CONCLUSIONS
  The proposed algorithm identified more infections than the WB-based algorithms in a high-risk MSM population. OF testing was associated with most of the discordant results between algorithms. HIV testing with the proposed algorithm can increase diagnosis of infected individuals, including early infections.
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States. Electronic address: svm6@cdc.gov.
authors.forename: Silvina
authors.initials: S
authors.lastname: Masciotra
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Smith
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Ae S
authors.initials: AS
authors.lastname: Youngpairoj
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Patrick
authors.initials: P
authors.lastname: Sprinkle
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Isa
authors.initials: I
authors.lastname: Miles
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Catlainn
authors.initials: C
authors.lastname: Sionean
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Paz-Bailey
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Johnson
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: S Michele
authors.initials: SM
authors.lastname: Owen
mesh_terms: D000465:Algorithms; D003955:Diagnostic Tests, Routine / Q000379:methods*; D015658:HIV Infections / Q000175:diagnosis* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000276:immunology; D015498:HIV-2 / Q000145:classification / Q000276:immunology; D018451:Homosexuality, Male; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D012680:Sensitivity and Specificity; D014481:United States; D014505:Urban Population
keywords: Algorithms; Diagnostics; HIV-1; Laboratory