Correlation of exam and non-exam factors with ultrasound positivity for deep vein thrombosis.

Rationale and objectives: First-line imaging for diagnosis of deep vein thrombosis (DVT) is ultrasound (US). Although Well's criteria and laboratory testing help inform best ordering practices, this investigation evaluates the influence of various patient and non-patient factors on exam results.

Materials and methods: This study analyzed structured reports from all inpatient and emergency department (ED) ultrasound exams across two institutions from 2015-2022. Examination, provider, and patient factors were compared to exam result for effect on exam result and inter-group variance.

Results: The overall rate of acute/new non-calf DVT was 10.4%. Rates of acute/new non-calf DVT were found to be higher in Inpatients (vs ED patients), upper extremities (vs. lower), patients with lower BMIs, Physicians (vs Advanced Practice Providers), and when ordered by providers with fewer overall DVT US exams ordered. Mixed results were observed for number of limbs examined and provider supervision status. Exam day of week and time of day were not significant.

Conclusions: DVT US results varied based on exam, facility, patient, and provider level factors, which can inform institutional quality monitoring programs, resource utilization, and future investigations into factors that may influence diagnostic testing results.