The American College of Radiology’s (ACR) Manual on Contrast Media divides adverse responses to intravenous (IV) iodinated contrast media into two categories: allergic-like (ALR) and physiologic (PR). Patients with mild or severe ALR who have had it previously recorded may benefit from premedication. For a study, researchers sought to determine whether listing an allergy to iodinated contrast media caused a delay in care, increased the use of non-contrast studies, and quantified the incidence of listing iodinated contrast allergies which do not require premedication by conducting a retrospective analysis of patients who underwent computed tomography (CT) imaging in the emergency department (ED).

A retrospective study of CT scans conducted in the emergency department of the academic medical center over a 6-month period was done. There were 12,737 distinct patients, and 454 of them had a known sensitivity to iodinated contrast. One hundred and six underwent IV contrast and were grouped according to whether premedication was required. Patient demographics, clinical features, and operational results were assessed using descriptive statistics. In addition, the time from order to start (OTS time) of CT imaging was predicted using a multivariate linear regression model while adjusting for covariates.

Contrast-enhanced CT imaging was performed on non-allergic patients more frequently than on allergic patients (45.9% vs. 23.3%, P<0.01). When contrast-enhanced CT imaging was performed on allergic patients, the OTS duration was 360 min, which was substantially greater than the OTS time for non-allergic individuals (118 min, P<0.001). The ACR criteria for requiring premedication were not met by 27 (25.5%) of the 106 allergic patients who received contrast-enhanced CT imaging. The average OTS time for these 27 patients was 296 minutes, which was substantially greater than the OTS for patients who were not allergic (118 minutes, P<0.01) and was similar to the OTS for the 79 patients who did match the premedication requirements (382 minutes, P=0.23). OTS duration was considerably longer if a contrast allergy was present, according to a multivariate linear model (P<0.001).

The time it took to have a contrast-enhanced CT scan was significantly longer when there was a charted iodinated contrast allergy. Patients who didn’t fulfill the ACR criteria for premedication nonetheless experienced this delay. The time of stay in the emergency department for these patients may be cut by nearly 4 hours by appropriately delaying premedication.