Diagnostic Imaging & Contrast Safety

Before any contrast-enhanced imaging study (CT with contrast, cardiac catheterization), screen for kidney function (contrast can cause acute kidney injury, especially in patients with pre-existing renal impairment, dehydration, or diabetes), allergy history (iodine-based contrast specifically, not general shellfish allergy, which is a common but outdated myth), and metformin use (held around the time of iodinated contrast per facility protocol, due to a rare but serious risk of lactic acidosis if kidney function is impaired afterward).