Purpose
Modern medical students rely on electronic resources for studying, but the ways students use these tools are unclear. The HistoLogic app was created in 2021 to supplement the histology curriculum, and we added cardiopulmonary tissues in 2024. We anticipated high usage rates because this system was regularly requested by students.

Methods
The HistoLogic app contains explore mode with didactic content, time trials mode with randomized multiple-choice questions, and hot streak mode where students try to beat their high scores. The first HistoLogic module was offered in Block 1 of the curriculum. The new cardiopulmonary module was released in Block 4, five months later. Two modules were available for gastrointestinal and renal systems the following month in Block 5. We examined the number of app logins and time usage on a weekly basis for each organ system. We also conducted surveys to evaluate how learners use the app to study.

Results
152/301 students (51%) installed the app at the start of the curriculum in Block 1. Block 1 had three histology labs with a total of 4.5 contact hours. 19/301 students (6.3%) used the app during Block 4 for cardiopulmonary content. Block 4 had two labs with 3 contact hours. 48/301 students (15.9%) used HistoLogic in Block 5, and 12 were new adoptees. Block 5 had four labs with 5 hours of contact time. 33/301 students completed the survey. 32/33 students (96.9%) agreed HistoLogic improved their histology knowledge.

Conclusions
Students agreed HistoLogic benefited their learning, but app usage was lowest in Block 4. This result may correlate with fewer Block 4 histology labs because Block 5 showed increased use with a higher number of labs. We will investigate the connection between contact hours and HistoLogic use with the addition of two organ systems this academic year.