Make sure that the ordering doctor knows you have the contrast allergy. Often, there are alternative ways to help answer the clinical question. Also, it is important to know the exact circumstance which led to you being told you have a contrast allergy. A “reaction” to a contrast injection – for example feeling warm or nauseated – might not be an allergic response at all. If you have a true allergic response to contrast, and there are no alternative studies that can be done, you can receive medication in advance to decrease the risk for allergic response. Be assured that if the facility that does your study knows of a previous allergic reaction they will be prepared with additional medications and treatments in the unlikely event you would need it.