Vironostika hiv 1 microelisa system

HIV diagnosis was determined by Food and Drug Administration (FDA)-approved HIV assays. In general, initial screening was conducted with an enzyme-linked immunoassay (ELISA) or an enzyme immunoassay (EIA). Assays used through the study period included Vironostika HIV-1 Microelisa System (bioMerieux, Durham, North Carolina, US), HIV AB HIV-1/HIV-2 (rDNA) EIA (Abbott Laboratories, Abbott Park, Illinois, US) and, currently, the ADVIA Centaur HIV 1/O/2 Enhanced (EHIV) (Siemens Healthcare Diagnostics, Tarrytown, New York, US). Samples that were screen-reactive were repeated in duplicate with the same assay. If two of three test results were reactive, the sample was reflexed to FDA-approved supplemental/confirmatory assays, HIV-1 Western Blot (Genetic Systems HIV-1 Western Blot, Bio-Rad Laboratories, Redmond, Washington, US) and/or an immunofluorescent antibody (IFA) test (Fluorognost HIV-1 IFA, Waldheim Pharmazeutika, GmbH, Vienna, Austria).

DBS samples were extracted by field workers according to the UNAIDS and WHO Guidelines for Using HIV Testing Technologies in Surveillance¹⁷ . The DBS samples were transported to the AHRI laboratory in Durban where HIV status was determined by antibody testing with a broad-based HIV-1/HIV-2 ELISA (Vironostika HIV-1 Microelisa System: Biomérieux, Durham, NC, USA) followed by a second ELISA (Wellcozyme HIV-1 + 2 GACELISA: Murex Diagnostics Benelux B.V., Breukelen, Netherlands). The AHRI laboratory has used the same HIV testing algorithm since 2005.
From the HIV surveys of 2011, 2013, and 2014, we obtained viral load measurements from all the HIV-positive DBS samples^{21 (link)}. Nucleic acid was extracted from the DBS samples with NucliSENS EasyMag (Bordeaux, France) and a Generic HIV Charge Virale (Biocentric, Bandol, France) test was used to quantify the viral load levels. The quantification method has a lower detection limit of 1550 copies/mL^{18 (link)}, which we defined as the threshold for detectable viremia.

Participants provided 7 ml venous blood after pre-test counselling to test for HIV, syphilis, and HSV-2. Enzyme-linked immunosorbent assay (ELISA) (Vironostika HIV-1 Microelisa System; bioMerieux, Durham, NC) was performed to screen for HIV-1 antibody, and Western Blot (HIV Blot 2.2 WBTM, Genelabs Diagnostics, Singapore) was used to confirm positive cases. Syphilis was screened using a Rapid plasma reagin (RPR) test (Shanghai Kehua Bio-engineering Co., Ltd, China), and positive cases were confirmed by Treponema pallidum particle assay (TPPA) (Hainan Huamei, China). Only samples with positive results on both screening and confirmation tests were deemed HIV/syphilis positive. ELISA (HerpeSelect-2, Focus Technologies, USA) was used to determine the presence of an HSV-2 antibody infection. Confirmed HIV-positive specimens were tested for BED HIV-1 capture enzyme immunoassay (BED-CEIA, Calypte Biomedical Corporation, Rockville, MD, USA) to determine recently infected (HIV infected ≤168 days) or chronically infected (HIV infected >168 days) status [21 (link)].

Venous blood samples were collected from all participants and tested for HIV and syphilis. HIV screening was conducted using an enzyme-linked immunosorbent assay (ELISA, Vironostika HIV-1 Microelisa System; BioMe´rieux), and a positive case was confirmed by the HIV-1/2 Western blot assay (HIV Blot 2.2 WB; Genelabs Diagnostics). Syphilis tests were conducted by ELISA and rapid plasma regain testing (diagnosis test; Shanghai Kehua, China). A participant who had positive results for both ELISA and rapid plasma regain testing was considered to have a current syphilis infection.