Impact of nucleic acid testing relative to antigen/antibody combination immunoassay on the detection of acute HIV infection

• Published in: AIDS (London) Vol. 29; no. 7; pp. 793 - 800
• Main Authors: De Souza, Mark S, Phanuphak, Nittaya, Pinyakorn, Suteeraporn, Trichavaroj, Rapee, Pattanachaiwit, Supanit, Chomchey, Nitiya, Fletcher, James L, Kroon, Eugene D, Michael, Nelson L, Phanuphak, Praphan, Kim, Jerome H, Ananworanich, Jintanat
• Format: Journal Article
• Language: English
• Published: England 24-04-2015
• Subjects: Adolescent; Adult; AIDS/HIV; Costs and Cost Analysis; Diagnostic Tests, Routine - methods; Female; HIV Infections - diagnosis; Humans; Immunoassay - methods; Lentivirus; Male; Middle Aged; Molecular Diagnostic Techniques - methods; Retroviridae; Sensitivity and Specificity; Thailand; Young Adult; Thailand; ISEW, Thailand
• ISSN: 0269-9370; 1473-5571
• DOI: 10.1097/QAD.0000000000000616

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 74 334 clients screened for HIV infection, HIV prevalence was 10.9% and the overall incidence of AHI (N = 112) 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 353 cells/μl and HIV plasma viral load was 598 289 copies/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.