Purpose: APOL1-associated kidney disease disproportionately affects people of African ancestry. Black American (BAs) potential living kidney donors require appropriate genetic counseling on APOL1 testing. However, access to such services is limited outside of academic medical centers. This study describes the development of a culturally tailored decisional support tool, Informed Decisions About APOL1 (IDEA), to aid BAs in making informed choices about APOL1 genetic testing (GT) for living kidney donation. 
Methods: IDEA was developed in three phases. Phase I involved designing a wireframe based on results from focus groups and surveys with BA potential living kidney donors and expert input covering key topics: kidney transplantation, APOL1 testing, common questions, decision-making considerations, and risks/benefits. In Phase II, the software company Nurelm assisted in the development of the app prototype. In Phase III, trained standardized healthcare providers guided BA participants through simulated consultations using the prototype. Participants completed pre- and post-encounter surveys and participated in virtual focus groups to provide feedback on the app prototype, leading to iterative refinements. 
Results: 30 BA participants engaged in four rounds of simulations. 60% were male (n=18), with an average age of 56.2 years (SD= 11.6). Post-encounter survey results indicated that 93.3% (n=28) of participants rated the app as either good, very good, or excellent, while 90% (n=27) found the app easy to use. All respondents reported that the app would be useful for individuals contemplating APOL1 GT. 93.3% of participants felt that they had enough information to make a decision about GT after completing the simulated consultation, and 90% reported that they would have opted to undergo GT. Main participant suggestions for improving the app included enhancing the aesthetics with brighter colors, streamlining the risks and benefits section, and adding more information and resources on inherited risk and live kidney donation. Refinements were made to the app following each round of simulations based on participant feedback. 
Conclusion: IDEA is a novel decisional support tool designed to facilitate informed decision-making among BA potential living kidney donors. The final phase of development will solicit feedback from a national sample of transplant professionals using a Delphi process.