BACKGROUND: The majority of patients with primary hyperparathyroidism (PHPT) are diagnosed without the classic signs of renal or osseous complications. Vague and subjective symptoms have been attributed to PHPT but have been difficult to measure during the medical encounter. The Patient-Reported Outcomes Measurement Information System (PROMIS) of the National Institutes of Health contains validated measures of physical and mental health that can be administered by the use of computer-adaptive testing (CAT). The objective of this study was to evaluate the feasibility of PROMIS assessment in the clinical setting to measure changes in patient-reported health before and after parathyroidectomy. We hypothesized that patients undergoing parathyroidectomy for PHPT would report greater improvement in mental and physical health compared with control patients. METHODS: Adult PHPT patients scheduled for parathyroidectomy and control patients requiring diagnostic thyroid operation were enrolled prospectively during a 6-month period. Patients were administered clinically relevant PROMIS health domains via CAT at a preoperative visit and 3 weeks after operation. A change in score of 5 or greater for each PROMIS instrument was defined as clinically important. Statistical significance of pre/post-surgery changes in scores was determined using paired t tests. RESULTS: A total of 35 patients with PHPT and 9 control patients completed the study. The mean number of PROMIS items answered during an assessment was 67 (range 51-121, SD 15.4). Median completion time was 8.2 minutes (range 3.4-38.4, SD 4.7). Clinically important improvement after parathyroidectomy in the PHPT group was greater than in the control group in 5 PROMIS domains. The score improvement experienced by PHPT patients was 8.8 in Fatigue, 6.7 in Sleep-Related Impairment, 5.0 in Anxiety, 7.0 in Applied Cognition, and 6.2 in Depression (all P < .05). CONCLUSION: PROMIS is an efficient clinical assessment platform for measuring patient-reported outcomes in PHPT via CAT. Several domains of physical and mental health in patients with PHPT show statistically and clinically important improvement after parathyroidectomy.