Synopsis
Assess kidney risk around iodinated contrast without withholding time-critical imaging, use proportionate prevention, and distinguish a temporal creatinine rise from injury truly caused by contrast.
- Contrast-associated AKI means an AKI occurring after contrast exposure; the timing does not prove that contrast caused it, particularly in acutely ill patients with sepsis, hypotension, surgery or other nephrotoxins.
- Current NICE guidance describes a small but increased risk with eGFR below 30 mL/min/1.73 m²; risk discussion should be individual rather than treating modest stable CKD as an automatic contraindication.
- When delay would be clinically significant, iodine-based contrast should not be withheld for a creatinine result or pre-hydration; the diagnostic benefit in emergency CT commonly outweighs the renal concern.
Key red flags
Recent vomiting, infection, hypotension, oliguria or a rising creatinine suggests acute dysfunction and makes an old eGFR unsuitable. Clarify urgency, correct reversible physiology and involve radiology or nephrology without obstructing essential emergency imaging.
Investigation priorities
Decide whether any renal assessment can safely occur before contrast and whether contrast is essential to answer the question.
Management branches
Contrast imaging is required for a condition in which delay may cause clinically important harm.
- 1. Confirm the time-critical clinical question with the responsible senior clinician and communicate known AKI, transplant status or advanced CKD to radiology.
- 2. Proceed without making creatinine measurement or prophylactic intravenous fluid a prerequisite, in keeping with NICE and the joint RCR–RCEM emergency position.
Key medicines
Sodium chloride 0.9% intravenous infusionFor selected particularly high-risk inpatients, use the current radiology and intravenous-fluid protocol; prescribe an individualised rate and duration rather than copying a universal regimen.
Isotonic sodium bicarbonate intravenous infusionAn alternative NICE-listed expansion fluid for particularly high-risk inpatients; concentration, preparation, rate and timing must follow the approved local contrast protocol.