Practical application of recombinant thyrotropin testing in clinical practice.

OBJECTIVE: To review the indications for use of recombinant thyrotropin (rTSH) and outline the details of implementation of rTSH diagnostic testing in patients with treated thyroid cancer. METHODS: We discuss the results of published clinical trials that have compared rTSH-stimulated testing with conventional withdrawal of thyroid hormone suppressive therapy. Appropriate candidates for rTSH testing are described, and the typical schedule for rTSH testing and follow-up is presented. An overview of coding and documentation for reimbursement is also provided. RESULTS: Clinical studies have found no significant difference in the combined sensitivity of (131)I scans and serum thyroglobulin measurements for detection of recurrent thyroid cancer after rTSH stimulation versus withdrawal of thyroid hormone therapy. As expected, patients have fewer symptoms and a more favorable mood state after use of rTSH. Patients with thyroid cancer who have undergone total or near-total thyroidectomy followed by 131I ablation can be considered for rTSH testing. For low-risk patients, two cycles of rTSH testing 1 to 2 years apart, followed by testing every 3 to 5 years, are recommended. For moderate- to high-risk patients who have undergone one cycle of negative levothyroxine-withdrawal testing, two cycles of rTSH testing at a 6- to 12-month interval, followed by testing every 1 to 3 years for at least the first decade of follow-up, are recommended. Most commercial insurance, Medicare, and Medicaid carriers now cover rTSH, either in a prescription drug plan or under major medical benefits. CONCLUSION: Radioiodine scanning and serum thyroglobulin measurement after intramuscular injection of rTSH are valuable new monitoring options in patients with treated thyroid cancer, avoiding the adverse effects of hypothyroidism.