Impact of nucleic acid testing relative to antigen/antibody combination immunoassay on the detection of acute HIV infection
To assess the addition of HIV nucleic acid testing (NAT) to fourth-generation (4thG) HIV antigen/antibody combination immunoassay in improving detection of acute HIV infection (AHI).
Participants attending a major voluntary counseling and testing site in Thailand were screened for AHI using 4thG HIV antigen/antibody immunoassay and sequential less sensitive HIV antibody immunoassay. Samples nonreactive by 4thG antigen/antibody immunoassay were further screened using pooled NAT to identify additional AHI. HIV infection status was verified following enrollment into an AHI study with follow-up visits and additional diagnostic tests.
Among 74â–Š334 clients screened for HIV infection, HIV prevalence was 10.9% and the overall incidence of AHI (Nâ–Š=â–Š112) was 2.2 per 100 person-years. The inclusion of pooled NAT in the testing algorithm increased the number of acutely infected patients detected, from 81 to 112 (38%), relative to 4thG HIV antigen/antibody immunoassay. Follow-up testing within 5 days of screening marginally improved the 4thG immunoassay detection rate (26%). The median CD4+ T-cell count at the enrollment visit was 353â–Šcells/Î¼l and HIV plasma viral load was 598â–Š289â–Šcopies/ml.
The incorporation of pooled NAT into the HIV testing algorithm in high-risk populations may be beneficial in the long term. The addition of pooled NAT testing resulted in an increase in screening costs of 22% to identify AHI: from $8.33 per screened patient to $10.16. Risk factors of the testing population should be considered prior to NAT implementation given the additional testing complexity and costs.
Document Type: Research Article
Affiliations: 1: SEARCH 2: Department of Retrovirology, Armed Forces Research Institute of Medical Sciences, United States Component, Bangkok, Thailand 3: The Thai Red Cross AIDS Research Centre, Bangkok, Thailand 4: United States Military HIV Research Program, Bethesda
Publication date: April 24, 2015