Table 2 Summary of ETD for Recommendation # 11

Original Recommendation

Follow-up within the first 1–2 months after RAI therapy for GD should include an assessment of free T4, total T3, and TSH. Biochemical monitoring should be continued at 4–6-week intervals for 6 months, or until the patient becomes hypothyroid and is stable on thyroid hormone replacement (Strong Recommendation; Low-Quality Evidence)

Modified Recommendation

Follow-up within 1–2 months after RAI therapy should include an assessment of free T4 only. Once FT4 is found to be low then a TSH should be checked. When TSH is high, that means post-radioiodine hypothyroidism has been achieved, and levothyroxine replacement for the patient should be started at approximate dosage 1.6 µg/kg, then recheck TSH no earlier than 6-8-weeks to assess adequacy of dose. FT4 should be monitored every 4–6 weeks for a duration of 6 months after RAI until it falls within the hypothyroid range. Once hypothyroid & on stable dose of levothyroxine, TSH should be measured every 6–12 months. (Conditional Recommendation; Low-Quality Evidence)

Overall Conclusion

☐Strong recommendation for Modified Recommendation

☒Conditional recommendation for Modified Recommendation

☐Conditional recommendation for either Original Recommendation or Modified Recommendation

☐Conditional recommendation for Original Recommendation

☐Strong recommendation for Original Recommendation

Additional Suggestions:• The frequency of TFTs can be decreased with time, to be decided on a case-by-case basis.• Timely monitoring of FT4 and initiation of thyroid hormone replacement as soon as the patient becomes hypothyroid will be beneficial to the patient. Once patient is on thyroid hormone replacement, TSH can be checked periodically for assessing adequacy of thyroid hormone replacement.• Public and private lab and hospitals/centers should consider combining RAI administration for thyrotoxicosis with its follow-up laboratory testing in a single package to promote compliance to follow-up testing.

Justification:• The results of TFTs at 1 month may be confusing for the clinician and may result in unnecessary treatment with thioamides.• FT4 is sufficiently sensitive for the purpose of follow-up testing. There is unlikely to be a major difference in outcomes with use of the FT4 alone instead of the full panel.