A nurse is preparing a 45-year-old client with a family history of glaucoma for fluorescein angiography. The client has no known kidney issues and takes no regular medications. Which nursing intervention is most important to implement before the procedure?

Assessing for allergies to contrast dyes is critical before fluorescein angiography due to risk of severe allergic reactions like anaphylaxis. Other interventions are important but less urgent for preventing life-threatening complications.

Understanding the Procedure and the Priority
Before any diagnostic procedure involving injectable contrast media, the nurse's most critical responsibility is to identify and prevent potentially life-threatening hypersensitivity reactions. Fluorescein angiography involves the intravenous injection of a dye (fluorescein sodium) to visualize retinal and choroidal circulation. Although fluorescein is not an iodine-based contrast agent, the clinical workflow for safe administration mirrors that of other injectable dyes. A thorough allergy assessment is a non-negotiable first step to ensure client safety.

Why Allergy Assessment is the Most Important Intervention
The primary concern with any intravenous dye injection is the risk of anaphylaxis or severe allergic reactions. The pre-procedural guideline for ophthalmic imaging emphasizes a standardized approach to patient preparation to mitigate risk. Assessing for allergies to iodine, shellfish, and contrast dyes serves as a broad screening tool. While a shellfish allergy indicates a reaction to a muscle protein (tropomyosin) and not directly to iodine or radiocontrast media, a history of any significant allergic reaction flags a patient as being at higher risk for hypersensitivity to other agents. This precautionary principle is embedded in preoperative imaging standards to ensure clinicians can predict outcomes and prepare for adverse events ^[1].

Analyzing the Incorrect Options
- Option 1 (Instruct the client to remove all jewelry and metal objects): This is a standard safety intervention for magnetic resonance imaging (MRI), not for fluorescein angiography. Angiography uses a specialized camera and a flash, not a magnetic field, making metal removal unnecessary for the procedure's function or safety.
- Option 2 (Ensure the client has been NPO for 8 hours prior to the procedure): Fasting is generally not required for fluorescein angiography. The dye is injected intravenously, and the procedure does not involve sedation or anesthesia that would compromise the airway. A client with diabetes, like the one in the scenario, should actually be advised to take their usual medications and eat a light meal to prevent hypoglycemia, unless specifically instructed otherwise.
- Option 3 (Administer prescribed mydriatic eye drops 30 minutes before the procedure): Pupil dilation is a necessary step to allow adequate visualization of the fundus. However, this is a dependent nursing action that follows a provider's order. The most important nursing intervention is the independent assessment of allergies, which must be completed and communicated before any medication, including mydriatic drops, is administered.

Special Considerations for the Client in the Scenario
The client has mild kidney disease and takes metformin. While fluorescein is primarily cleared by the kidneys, it is not known to be directly nephrotoxic in the way certain iodinated contrasts can be. The specific concern with metformin and contrast media relates to the risk of lactic acidosis, a rare but serious complication historically associated with older iodinated contrast agents in patients with renal impairment. Current guidelines for fluorescein angiography do not typically mandate withholding metformin, as the dye does not carry the same risk profile. Nevertheless, the assessment of kidney function and medication reconciliation are vital parts of the pre-procedure checklist, reinforcing why a comprehensive nursing assessment—starting with allergies—is the foundational step for safe, individualized care ^[1].