Evaluation of an alternative HIV diagnostic algorithm using specimens from seroconversion panels and persons with established HIV infections

Expansion of HIV screening to non-clinical venues is aided by the use of dried blood spots for Western blot confirmation

“…Since 2004, confirmation of all reactive rapid tests by Western blot or immunofluorescent assay has been required [17]. However, the currently available rapid tests will detect HIV infection during seroconversion before the Western blot becomes positive [18]. In addition to its relative insensitivity, the Western blot is labor intensive, can be difficult to interpret and lacks the ability to differentiate HIV-1 and HIV-2 antibodies.…”

Human Immunodeficiency Virus

“…Later, the introduction of luminescent chemicals for detection in chemiluminescence assays offered shorter incubation and reaction times, decreasing test turnaround time. In addition, third-generation assays detect patient IgG and IgM, allowing for earlier detection of HIV antibody production, well before WB positivity, and reducing the window period to 3 to 4 weeks (18,19).…”

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

“…The supplemental/confirmatory assays use viral lysate antigens and are designed for IgG detection only (1st generation IA). The latest FDA-approved laboratory-based screening assays can detect HIV p24 Ag and IgM and IgG antibodies against HIV-1/2 (4th generation IA) and have better sensitivity than other generation IAs, including WB, during early HIV-1 infection [2][3][4][5][6][7][8]. In early stages of infection, from the acute period to the appearance of IgG, WB fails to confirm infection detected by nucleic acid amplification testing (NAAT) or p24 or containing only IgM antibodies.…”

“…In early stages of infection, from the acute period to the appearance of IgG, WB fails to confirm infection detected by nucleic acid amplification testing (NAAT) or p24 or containing only IgM antibodies. In early HIV-1 infections, reports indicate that NAAT is positive 26 days before the WB becomes positive and 4th generation IAs detect infection approximately 19 days before the WB becomes positive [2,6].…”

“…An alternative algorithm that involves screening with a sensitive 4th generation-IA, followed by HIV-1/HIV-2 antibody differentiation IA, has been proposed by the the Centers for Disease Control & Prevention [15][16][17]. Specimens reactive on a 4th generation IA are tested with a differentiation assay which has been shown to be more sensitive than WB during early HIV infection and allows discrimination of HIV-1 from HIV-2 infections [6,18,19]. Specimens testing negative or indeterminate (i.e., discordant results) in the differentiation assay are resolved by NAAT.…”