Hiv ag ab combo assay

Venous blood (10 mls) collected into EDTA was processed within 8 h at the Zambart central laboratory. This laboratory was registered under the College of American Pathologists (CAP) External Quality Assurance (EQA) programme for the Abbott Architect HIV Ag/Ab Combo assay and a certified laboratory by the National Institutes of Health HIV Prevention Trials Network (HPTN).
The whole blood was centrifuged at 800 × g for 10 min and plasma stored at − 80 °C. All plasma samples were tested according to a composite reference standard algorithm as shown in Additional file 1: Fig. S1 (Laboratory Reference Standard).
All samples were tested using the Abbott Architect HIV1 Ag/Ab combo EIA test. Reactive tests on this assay were confirmed using a second 4th generation assay, Bio-Rad GS HIV Combo Ag/Ab assay (Bio-Rad, Hercules, CA, USA). Any discrepant results were retested using Geenius and HIV RNA testing (Additional file 1: Fig. S1). Cut-off points and interpretation criteria for all laboratory tests were as specified by the manufacturer. On samples with discrepant results, we additionally conducted viral load testing and RDT testing using plasma was rather than whole blood.
Laboratory reference standard results were not provided to study participants. Laboratory testers were not blinded to the OraQuick® HIV Self-Test or RDT results of the study participants.

Using a 25 item questionnaire, Hein&Fiete collected data on demographics (age, migration status, education), sexual orientation and partnerships, number and gender of sex partners in the previous 12 months, place where sex partners were met, use of drugs in combination with sex, testing history and test results for HIV and STIs, reasons for testing, condom use and reasons for not using condoms, and risk management strategies other than condom use.
Clients were tested for HIV with the Abbott Architect HIV Ag/Ab Combo assay, reactive samples were confirmed by Mikrogen, recomLine HIV-1 & HIV-2 IgG testing. For syphilis testing, samples were screened by Abbott Architect Syphilis TP Reagent, and confirmed by a quantitative TPPA test (MAST). Active infection was defined as either detection of anti-treponemal IgM (Mikrogen, recomWell Treponema IgM) or a positive test for Cardiolipin-KBR (Virion). Pharyngeal swabs taken by medical personnel and rectal swabs taken by the clients themselves were tested for gonorrhoea (Gc) and Chlamydia trachomatis (CT) with the BD ProbeTec™ ET System, which uses strand displacement amplification (SDA) for real-time detection of CT/GC.