Methods:A retrospective chart review was performed on all patients who have undergone skin tests for previous HSR to ICM at the Seoul National University Hospital during June 2011 to March 2015. Iobitridol, iohexol, iomeprol, iopamidol, iopromide, ioversol, and iodixanol were used for testing.
Results:A total of 180 patients had been tested during the study period. The mean number of ICM agents tested per patient was 6.3 (range 5-7). Skin tests were positive in 68 patients (37.8%). Higher skin test positivity was associated with previous HSR severity(mild 25.4%, moderate 37.5%, severe 52.6%; p < 0.01) and shorter testing interval after HSR (within 2 months 61% vs beyond 2 months 29%; p<0.001). The ICM agents most frequently found positive were iopromide, iohexol, and iomeprol. Twenty-three of the 68 skin-test-positive patients (34%) were positive to two or more ICM. The cross-reactivity for each skin-test-positive ICM is as follows: iopromide-positive patients (most cross-reactive: iohexol 28%; least cross-reactive: iodixanol 3%); iohexol-positive (iopromide 35%; ioversol 4%); iomeprol-positive (iohexol 44%; iopamidol 0%); iobitridol-positive (iopromide 31%; iodixanol 0%); iodixanol-positive (iohexol 50%; iobitridol 0%); ioversol-positive (iobitridol 40%, iopamidol 0%); iopamidol-positive (iopromide 100%, ioversol 0% ).
Conclusion: We report data on ICM skin-test cross-reactivity which can be helpful in guiding the choice of an alternate ICM in situations where skin tests are not available. Further studies with ICM re-challenge data are needed for better understanding of ICM cross-reactivity.