Contrast Medium Reactions Workup

Updated: Jul 22, 2017
  • Author: Nasir H Siddiqi, MD; Chief Editor: Eugene C Lin, MD  more...
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Workup

Approach Considerations

A pertinent patient medical history should be obtained, and the following elements should be stressed: history of allergies, asthma, diabetes mellitus, renal insufficiency, and/or cardiac diseases; currently or recently used medicines; possibility of pregnancy; and previous contrast agent administration. If the patient had a reaction in the past, the nature of the reaction must be determined. Also, serum creatinine levels should be determined. [41, 42]

Skin testing

Brockow et al performed a prospective study to determine the specificity and sensitivity of skin tests in patients who have experienced contrast-related reactions and found that skin test specificity was 96-100%. Skin prick, intradermal, and patch tests were conducted in 220 patients with either immediate or nonimmediate reaction. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. The data suggested that at least 50% of hypersensitivity reactions to contrast media are caused by an immunologic mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors. [13]

In a retrospective study of 37 patients with suspected immediate hypersensitivity reaction to iodinated contrast media (ICM), the negative predictive value for skin tests and intravenous provocation test (IPT) with low dose ICM was 80% (95% CI 44-97%). [43]