Background: At-risk alcohol use is important to identify in clinical settings to facilitate interventions. The Patient-Reported Outcomes Measurement Information System (PROMIS) Alcohol Use Short Form was developed through an item response theory process, but its utility as a screening instrument in clinical care has not been reported. Objective: To determine the ability of the PROMIS Alcohol Use Short Form to identify people with current or future at-risk alcohol use defined by the Alcohol Use Disorders Identification Test consumption (AUDIT-C) instrument. Methods: Observational study of people living with HIV (PLWH) in clinical care at four sites across the US. Patients completed a tablet-based clinical assessment prior to seeing their providers at clinic appointments. We used 3 definitions of clinically-relevant at-risk alcohol use and determined the proportion of PLWH with current or future at-risk drinking identified by the PROMIS instrument. Results: Of 2497 PLWH who endorsed ≥1 drink in the prior 12 months, 1500 PLWH (60%) endorsed "never" for all PROMIS items. In that group, 26% had clinically-relevant at-risk alcohol use defined by one or more AUDIT-C definitions. At follow-up (N = 1608), high baseline PROMIS scores had 55% sensitivity for at-risk drinking among those with at-risk drinking at baseline, and 22% sensitivity among those without baseline risk. Conclusions: The PROMIS Alcohol Use Short Form cannot be used alone to identify PLWH with clinically-relevant at-risk alcohol use. Optimal assessment of problem drinking behavior is not clear, but there does not seem to be an important role for the PROMIS instrument in this clinical setting.