Evaluation of Geenius HIV-1/2 Confirmatory Assay for the confirmatory and differential diagnosis of HIV-1/HIV-2 in Japan and reliability of the Geenius Reader in the diagnosis of HIV-2

Abstract

Background NEW LAV BLOT I and II (LAV I and LAV II), they were only option for human immunodeficiency virus (HIV) confirmatory test, following HIV screening test using HIV Ag/Ab combination test in Japan. We evaluated the performance of Geenius HIV-1/2 Confirmatory Assay (Geenius), both as a confirmatory test and for differentiation between HIV-1 and HIV-2, in comparison with LAV I and LAV II. Methods Eighty-nine HIV-1-positive plasma specimens, one anti-HIV-1 low-titer performance panel, 10 seroconversion panels, and two anti-HIV-1/2 combo performance panels were tested. The results were read with the Geenius Reader and by visual reading. Results All 89 HIV-1-positive plasma specimens were identified as HIV-1-positive using Geenius; this 100% success rate was superior to that with LAV I (95.5% using WHO criteria, 98.9% using CDC criteria). The HIV-1-positive specimens showed low cross-reactivity with HIV-2 lines in Geenius. The sensitivity of Geenius for HIV-1 detection was the same as or greater than that of LAV I, but less than that of Genscreen HIV Ag-Ab ULT, in our analysis of the commercial performance and seroconversion panels. In contrast, five of the 13 HIV-2-positive specimens that had been identified as HIV-positive untypable by visual reading because of their cross-reactivity to HIV-1 lines were successfully identified by the Geenius Reader as HIV-2-positive with cross-reactivity. Conclusions Geenius provides strong performance for HIV confirmatory tests and HIV-1 differentiation tests. However, when visual reading is used, its performance in HIV-2 differentiation is less reliable. Because HIV-2 infection has been sporadically reported in Japan, the use of the Geenius Reader is preferable to ensure more reliable HIV-1/HIV-2 differentiation.

Are Confirmatory Assays Reliable for HIV-1/HIV-2 Infection Differentiation? A Multicenter Study

“…On the opposite, assays designed only to identify HIV-2 infection, HIV-2 Blot 1.2 and New Lav Blot II, exhibited high rates of undetermined results and misclassified as HIV-2 some HIV-1 only infections (7% and 5%, respectively), a consequence of cross-reactivity between HIV-1 antibodies and HIV-2 proteins. These results are consistent with previous studies regarding HIV-1 infection sensitivities and undetermined results for INNO-LIA (27,36,37), HIV Blot 2.2 (36,38), New Lav Blot I and II (39,40) and Geenius (27, 36-39, 41, 42), summarized in Fig. 1.…”

“…New Lav Blot II and HIV-2 Blot 1.2 had reported sensitivities of at least 95% (32,43). INNO-LIA had a reported sensitivity of 100% (36,37), while sensitivity ranged from 85% to 100% for Geenius (27,(39)(40)(41)(42)44). However, most of these studies included a very limited number of patients.…”

Establishment of qualitative human immunodeficiency virus type 1 nucleic acid amplification test as an adjunct confirmatory test in low-prevalence areas and small- and medium-sized diagnostic laboratories

“…Livant et al reported that two of 16 pre-seroconverted specimens that were HIV-1 RNA-positive were also HIV-2 gp140-reactive [ 11 ]. In our previous study, four of 89 (4.5 %) HIV-positive samples cross-reacted with the HIV-2 gp140 line, although all were identified as HIV-1-positive when analyzed using Geenius Reader [ 13 ]. Thus, HIV-2 gp140-reactive cases could be related to the cross-reactivity of anti-HIV-1 Abs or nonspecific reactions.…”