To investigate the impact of universal testing accommodations on a computer-based reading comprehension test, accessibility, reliability, and validity were evaluated. Tests with and without accommodations were administered to 131 twelfth-grade students in three U.S. schools. Scores on Curriculum-Based Measurement probes determined groups of students without functional impairment (n = 83) and students with functional impairment (n = 44) in the access skill of reading fluency. Results indicated that ability in access skills is associated with use of accommodations, and that high accessibility can assist in removing the impact of construct-irrelevant skill. No score boost or differential boost was found; validity evaluation offered meaningful results. No reliability change was found. The results of this study support child study team members individualizing accommodations to target deficits in access skills, selecting accommodations on criteria other than differential boost, and offering appropriate accommodations more universally.