Since 1993, the HIV-1 WB assay (Bio-Rad Laboratories, Redmond, WA, USA) has been used as a confirmatory test to detect the presence of anti-HIV-1 IgG ( 5). Per the HIV diagnostic algorithm of Quebec, specimens with repeatedly reactive EIA/CMIA results undergo confirmatory testing at the Public Health Laboratory of Quebec. In the province of Quebec, HIV screening is performed using mainly fourth-generation enzyme immunoassays (EIA) or chemiluminescence microparticle immunoassays (CMIA) ( 4). The national guidelines for the diagnosis of HIV infection recommend the use of a two-step algorithm in which specimens are first tested using an HIV-1/2-sensitive screening assay followed by a more specific confirmatory assay, such as Western blot (WB) ( 3). The estimated incidence rates in Canada and Quebec are 7.2 and 3.4, respectively, per 100,000 people ( 1, 2). HIV prevalence is considered low in Canada, with an estimated rate of 212 per 100,000 people among infected people, 21% are unaware of their infection ( 1).

The performance of this new confirmatory assay to detect early infections, to reduce the rate of indeterminate status, and to confirm HIV-1 infection in cadaveric blood samples makes Geenius a potent reliable alternative to the WB.Īccurate laboratory diagnosis of human immunodeficiency virus (HIV) infection is essential for identifying individuals who could benefit from antiretroviral therapy and for reducing the risk of HIV transmission. Our results indicate that the Bio-Rad Geenius HIV 1/2 rapid test exhibits better sensitivity to detect HIV-1 infections and better performance than WB to confirm and differentiate between HIV-1 and HIV-2 infections. Ninety cadaveric samples (54 negative, 23 HIV-1 positive, and 3 HIV-1 indeterminate) were tested with Geenius, leading to a sensitivity of 100%, a specificity of 96%, and an indeterminate rate of 4%. However, 7% and 10% of them were indeterminate with Geenius and WB, respectively, leading to a specificity rate of 93% for Geenius and 90% for WB. None of the HIV-negative samples were positive using Geenius or WB.

Three of 10 patients presenting with an early HIV infection (1 to 2 weeks before seroconversion by WB) were positive using Geenius. Geenius reduced the number of indeterminate results by 85% and exhibited a differentiation capacity for HIV-1 and HIV-2 of 100% and 89%, respectively.

Sensitivity of the Geenius assay to detect HIV-1 and HIV-2 infections was 100% and 97%, respectively, and that of the WB assay was 86% and 39%, respectively. A total of 370 retrospective samples collected from 356 patients were tested. The rapid confirmatory Bio-Rad Geenius HIV 1/2 assay was evaluated as an alternative to the HIV-1 Western blot (WB) confirmatory assay.

Bio rad western blot kit