Negative Predictive Value of Allergologic Work-Up with Iodinated Contrast Media in 'Real-Life' Practice.

Background

Several strategies such as premedication or allergologic work-up have been used to facilitate safe iodinated contrast media (ICM) application. The aim of this study was to assess the negative predictive value of skin tests and complete allergologic work-up with iodinated contrast media in real-life settings.

Methods

We retrospectively enrolled 210 patients with a history of immediate hypersensitivity reactions to ICMs. The stepwise protocol of selecting safe ICMs included skin prick tests (SPTs), intracutaneous tests (ICTs), and intravenous drug provocation tests (DPTs). The tests were performed with one or more of the following medications: iohexol, iodixanol, iomeprol, iopromide, and ioversol. At least 6 months after selecting safe ICMs, a telephone follow-up was scheduled. Based on this data, negative predictive values of skin tests and the whole work-up were calculated.

Results

Overall, we obtained the following rates of positive tests: SPT-12% (55/441); ICT-10% (40/383); and DPT-5% (10/195). The highest rates of positive work-ups were found in patients tested within 1 year after the reaction and patients with a history of urticaria/angioedema after ICMs. The skin tests and DPTs determined a safe ICM in 184/210 (87%) patients. The negative predictive value of skin tests in reference to DPTs in hospital settings was 95%. Finally, a telephone follow-up demonstrated that 75/184 participants (41%) had been given the recommended ICM, including 68 cases (37%) with no subsequent hypersensitivity reaction and 7 (4%) with a reaction. The negative predictive value of allergologic work-up consisting of SPTs, ICTs and DPTs in real-life settings was 90%.

Conclusions

Skin tests and intravenous drug provocation tests with ICMs are characterised by high negative predictive value, and enable the determination of safe ICMs for most patients.