Table 2.

Summary of emergent domains and themes

Domain	Subthemes
Barriers to in-person STI testing	• Individual-level barriers (i.e., lack of knowledge) • Interpersonal-level barriers (i.e., controlling partners, difficulty talking to parents/guardians, fear of peer ridicule, fear of interaction with health-care providers, fear of positive results) • Structural-level barriers (i.e., transportation, cost, insurance navigation, treatment cost)
Concerns about mail-in STI testing	• Concern about accuracy of self-collected sample • Reservations about the platform • Concern about treatment costs
Youth preferences and opportunities to improve mail-in STI testing	• Improvements to ordering a kit (i.e., info on accuracy of kit, credibility of the platform, discreet packaging, info on treatment, shipping options) • Improvements to receiving kit and swabbing (i.e., tracking options, increasing availability of places to swab, swabbing instructions, support and hotline options) • Improvements to the post-testing experience (i.e., availability of support and resources after testing, tracking options) • Improvements to the testing results experience (i.e., multiple communication options, communication preferences, availability of health-care provider support)

STI = sexually transmitted infection.