What are the normal ranges of Radioactive Iodine Uptake (RAIU) test results?

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Last updated: February 24, 2025 • View editorial policy

From the Research

Normal RAIU values are generally considered to be between 10-35% at 24 hours after administration, as indicated by the most recent and highest quality study 1.

RAIU Test Results

The RAIU test is used to evaluate thyroid function and differentiate between various thyroid conditions.

  • Normal RAIU values typically range from 10-35% at 24 hours, as supported by the study published in 2020 1.
  • Low uptake is considered below 10% at 24 hours, which may suggest thyroiditis, exogenous thyroid hormone, or iodine excess.
  • High uptake is above 35% at 24 hours, often indicating conditions like Graves' disease or toxic nodular goiter.

Interpreting RAIU Results

It's essential to interpret RAIU results in conjunction with clinical symptoms and other thyroid function tests for accurate diagnosis.

  • Factors like recent iodine exposure or certain medications can affect RAIU results, so these should be considered when interpreting the values.
  • The study published in 2012 2 also highlights the importance of considering 24-hour RAIU values in predicting the outcome of radioiodine therapy in patients with diffuse toxic goiter.

Clinical Considerations

In clinical practice, it's crucial to consider the patient's overall clinical presentation and medical history when interpreting RAIU results.

  • The study published in 2020 1 suggests that patient-specific anatomical models may be necessary for accurate radioiodine dosimetry in the treatment of hyperthyroidism.
  • However, the study also notes that acquiring computed tomography (CT) images for patient-specific modeling may impose additional radiation dose to patients, and therefore, should be used judiciously.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.