s it possible for a patient to get a delayed reaction to IV contrast?

Yes. Delayed reactions occur from more than 30-60 minutes post injection to 1 week post injection. The majority occur between 6 and 12 hours. "Delayed Adverse Reactions to contrast media are not rare but are often not recognized as being linked to contrast administration and may be falsely ascribed to other drugs, These side effects are problematic because the patient is usually without medical supervision." Delayed Adverse Reactions to Parental Administration of Iodinated Contrast Media Egbert RE et al. AJR 2014; 203:1163-1170 "Immediate reactions occur at the time of injection to 1 hour after contrast administration, with most occurring within the first 5 minutes. These reactions may be either allergiclike or chemotoxic." Delayed Adverse Reactions to Parental Administration of Iodinated Contrast Media Egbert RE et al. AJR 2014; 203:1163-1170 "Delayed reactions are defined as an adverse event occurring from more than 30-60 minutes to 1 week after the administration of contrast media. The majority of these reactions have been shown to occur between 6 and 12 hours after contrast administration." Delayed Adverse Reactions to Parental Administration of Iodinated Contrast Media  Egbert RE et al. AJR 2014; 203:1163-1170 "The ACR states that most cases of DARs are self limited and require no or minimal treatment. In cases of moderate or severe reactions that are progressive or widespread the ACR recommends antihistamines, corticosteroids, or both for skin manifestations; antipyretics for fever; antiemetic's for nausea; and fluid resuscitation for hypotension." Delayed Adverse Reactions to Parental Administration of Iodinated Contrast Media Egbert RE et al. AJR 2014; 203:1163-1170 "A delayed reaction is defined as a reaction which occurs 1 hour to 1 week after contrast injection, which is predominately skin reaction. Iso-osmolar non-ionic contrast media have higher incidence of delayed adverse reactions." Adverse reactions to Intravenous Iodinated Contrast Media: A Primer for Radiologists  Namasivayam S et al.  Emerg Radiol (2006)12; 210-215