Background <p>Mobile cancer-testing services can widen access by taking testing to community or workplace sites. But the test is only one part of the pathway: eligibility explanation, informed choice, privacy, documentation, result communication, referral, and follow-up move outside clinics. Unless specified before rollout, these tasks can make a service easier to attend but harder to govern. In diagnostic-test development, a Target Product Profile is an advance brief defining a test’s intended users, use setting, and minimum and preferred features. To create an equivalent brief for outreach services, we adapted that approach into an implementation-aware Target Product Profile (iTPP). The iTPP turns evidence on delivery and handover into a requirement register, separating what must be in place, what would improve quality, what depends on local set-up, and what needs further evidence.</p> Methods <p>We conducted a qualitative method-development study using the Man Van mobile prostate-specific antigen (PSA) testing pathway as an exemplar, not an effectiveness evaluation. We interviewed attenders (<i>n</i> = 23), planning and delivery stakeholders (<i>n</i> = 13), and prospective stakeholders (<i>n</i> = 11). Using the Framework Method and abductive analysis, we charted interview evidence, converted delivery and handover issues into requirement statements, judged consequences of absence, and placed unresolved quantitative or operational questions in an Evidence and Decision Agenda.</p> Results <p>The method produced a Man Van-derived register with 42 attributes across six clusters: outreach legitimacy; privacy and dignity; deliverability; test acceptability and performance uncertainty; counselling and next steps; and data integration with primary care. Handover requirements centred on result ownership, record integration, safety-netting, and loop closure: documented responsibility acceptance by a named receiving service when action was required. Diagnostic thresholds, referral ratios, staffing ratios, outreach pacing, unit costs, and equity effects were treated as questions for further evidence, not universal requirements.</p> Conclusions <p>The iTPP is a pre-rollout method for specifying mobile outreach cancer-testing pathways before local adaptation, implementation, or evaluation. It identifies what should be preserved, what can vary by context, and what should remain open until stronger evidence is available. This PSA exemplar demonstrates the method; it does not establish service effectiveness, validate iTPP as an independent instrument, or recommend population screening.</p>