Oral Fluid Concentrations of Tenofovir and Emtricitabine for Monitoring HIV Antiretroviral Adherence: Findings From a Randomized Trial with Directly Observed Therapy (TARGET Study)

FTC can be detected in oral fluids and may be a promising pharmacologic marker for identifying recent PrEP non-adherence as early as one dose missed. TFV had lower concentrations in oral fluids, and is not suitable for adherence monitoring. <b>Clinical Trials Registration.</b> NCT0301260.