Radiologists make more errors interpreting off-hours body CT studies during overnight assignments as compared with daytime assignments

Background: There is increasing research attention on the impact of overnight work on radiologist performance. Prior studies on overnight imaging interpretive errors have focused on radiology residents, not on the relative performance of board-eligible or board-certified radiologists at night compared with during the day. Purpose: To analyze the rate of clinically important interpretation errors on CT examinations of the abdomen, pelvis, or both (“body CT studies”) committed by radiology fellows working off-hours based on day or night assignment. Materials and Methods: Between July 2014 and June 2018, attending physicians at one tertiary care institution reviewed all body CT studies independently interpreted off-hours by radiologists in an academic fellowship within 10 hours of initial interpretation. Discrepancies affecting acute or follow-up clinical care were classified as errors. In this retrospective study, the error rate for studies interpreted during the day (between 7:00 am and 5:59 pm) was compared with that of studies interpreted at night (between 6:00 pm and 6:59 am). Error rate in the first half of day and night assignments was compared with error rate in the latter half. Statistical analyses used x² tests and general estimating equations; significance was defined as P , .05. Results: There were 10 090 body CT studies interpreted by 32 radiologists. Forty-four of 2195 daytime studies (2.0%) had errors compared with 240 of 7895 nighttime studies (3.0%; P = .02). Twenty-two of 32 (69%) radiologists had higher error rates for night cases (P = .03). There were more errors in the last half of a night assignment (125 of 3358, 3.7%; P = .002) compared with the first half (115 of 4537, 2.5%). Conclusion: On the basis of a subspecialty review, clinically important off-hours body CT interpretation errors occurred more frequently overnight and more frequently in the latter half of assignments, with more radiologists having worse error rates at night compared with the day.