title: Evaluation of a rapid antigen and antibody combination test in acute HIV infection.
abstract: BACKGROUND
  New strategies at implementing HIV testing including rapid HIV assays are highly recommended to avoid late diagnosis. To shorten the diagnostic window period, the first point-of-care HIV assay, Determine HIV ½ Ag/Ab Combo (D4G, Alere, I) for the combined detection of p24 and anti-HIV antibody has been recently marketed and mainly tested in high prevalence setting.
  
  
  OBJECTIVE
  To establish D4G performances in acute HIV infection (AHI) in a setting at low HIV-1 prevalence.
  
  
  METHODS
  D4G performances were compared with HIV-1 RNA levels in a panel of well-characterized serum specimens from 17 patients with AHI. For specificity, 124 anti-HIV negative serum specimens from patients seeking HIV testing were studied.
  
  
  RESULTS
  D4G detected HIV infection in 15/17 patients. D4G antigen was positive in only 5 patients (29.4%), 4 of them with a viral load >10 million copies/mL. D4G antibody was reactive in other 10 patients (sensitivity: 58.8%, viral load from 70,161 to 8,120,000 copies/mL). Combined D4G sensitivity for acute HIV-1 infection was 88.2%; no false positive or invalid result was recorded (100% specificity, positive and negative predictive values: 100% and 98.4%, respectively).
  
  
  CONCLUSIONS
  In spite of a poor antigen sensitivity with optimal performances only for viral load >10 million copies/mL, D4G performances in acute HIV-1 infection were enhanced by the addition of p24 testing to the antibody. Improved HIV rapid testing to shorten the window period is important as rapid tests play a major role in expanding access to HIV testing and preventing HIV transmission.
authors: Laboratory of Microbiology and Virology, Infectious Diseases Department, Amedeo di Savoia Hospital, Turin, Italy.
authors: Silvia
authors: S
authors: Faraoni
authors: Andrea
authors: A
authors: Rocchetti
authors: Franca
authors: F
authors: Gotta
authors: Tina
authors: T
authors: Ruggiero
authors: Giancarlo
authors: G
authors: Orofino
authors: Stefano
authors: S
authors: Bonora
authors: Valeria
authors: V
authors: Ghisetti
mesh_terms: D000208:Acute Disease; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000097:blood*; D016022:Case-Control Studies; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D011933:Reagent Kits, Diagnostic