What should be evaluated in a patient's history before a CT scan?

Evaluating a patient's history for allergies to contrast materials is crucial before performing a CT scan because many of these procedures involve the use of intravenous contrast agents to enhance the visibility of structures within the body. Patients who have a known allergy to iodine or other components of the contrast material may experience serious reactions, such as anaphylaxis or other adverse effects, which can be harmful and require immediate medical attention.

By identifying any previous allergic reactions, healthcare professionals can take the necessary precautions, such as premedicating the patient with antihistamines or steroids, using a different imaging modality that doesn’t require contrast, or exploring alternative contrast agents that may be safer for the patient.

While height and weight can be pertinent for calculating dosages and radiation exposure, previous surgeries may help assess surgical history but are not as critical as knowing about allergies to contrast media. Additionally, a medication list is important for understanding potential interactions and effects on the patient's health but does not address the immediate risk of contrast reactions, which is why evaluating for allergies to contrast materials stands out as the most vital step in the pre-CT scan assessment.