RESUMEN
Acceptability of rapid HIV self-testing is high but potential users remain concerned about correct use, interpretation of test results, and linkage to care. This article describes user preferences for a smartphone app to mitigate these challenges and how these were integrated into the SMARTtest app to support self- and partner-testing using the INSTI Multiplex®. Sixty men and transgender women who have sex with men self-tested for HIV and syphilis while guided by a prototype app that provided a video, pictorial step-by-step instructions, and sample test results presented textually ("positive," "negative"). Subsequently, participants provided feedback on revisions and additional app content. Participants recommended offering different user modes (self, partner, both), and retaining the video, step-by-step instructions, and textual test results. They strongly favored the ability to save and send test results to sexual partners or providers. These features were integrated into the SMARTtest app to facilitate HIV/syphilis self- and partner-testing, HIV/syphilis status awareness and disclosure, and linkage to care.