For a hyperactive thyroid workup including protein-bound iodine, T3, and T4 tests, what should the nurse verify to ensure accurate results?

• A. Allergies to seafood
• B. Consumed more protein than usual
• C. Had anything to drink before the test
• D. Had recent x-rays using radiopaque dye

Answer: (D)

External iodine exposure can skew thyroid test results. Radiopaque contrast used in imaging contains iodine, which adds to the body's iodine pool. This excess iodine can alter the thyroid’s hormone synthesis and the measurements used in the workup (including protein-bound iodine, T3, and T4) by temporarily changing how much hormone is produced and how iodine is bound and detected. Because of this interference, results may be inaccurate if tests are done soon after contrast administration. The nurse should verify whether the patient has recently received iodinated contrast and plan to delay testing or note the timing to interpret results correctly. Other factors like seafood allergies, protein intake, or fluids before the test do not have the same impact on these thyroid tests.