HIV Infection Detection and ARV Monitoring in Kenya

The LAg-avidity assay was used to detect recent HIV infection at the central laboratory from serum samples in KAIS 2007 and dried blood spots (DBS) in KAIS 2012, while in KENPHIA, plasma was used with DBS available as a backup in case plasma was not available or depleted by preceding tests. LAg-avidity kits from Sedia Biosciences (Portland, OR) were used for testing plasma or serum samples, while DBS samples were tested using kits from Maxim Biomedical (Rockville, MD). KAIS 2012 used DBS to measure HIV RNA levels using the Abbott M2000 Real-Time HIV-1 Assay (Abbott Laboratories, Abbott Park, IL). For KENPHIA, RNA measurement was performed on plasma using the automated Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) HIV-1 RNA quantitation test (Roche Molecular Systems, Inc., Pleasanton, CA) or on DBS with the Roche CAP/CTM Free Virus Elution (FVE) Protocol.
DBS were tested to qualitatively detect ARVs in blood using tandem mass spectrometry liquid chromatography in all three surveys.^{22 (link)} The panel of ARVs evolved over time, reflecting changes in treatment guidelines: the ARVs tested for in the 2007 and 2012 surveys included nevirapine, efavirenz, lamivudine, and lopinavir, while in the 2018 survey, efavirenz, nevirapine, and atazanavir were included. Due to varying pharmacokinetics, efavirenz and nevirapine can be detected for up to 28 and 9 days, respectively, while the other included drugs can be detected for 1–3 days postingestion on DBS before their levels fall below the assay limit of detection due to their shorter half-lives.^{23 (link)} ARV testing was conducted at the University of Cape Town in 2014 for KAIS 2007 and 2012 and in 2019 for KENPHIA.