Ways to raise TSH levels for accurate test results

Your doctor will give you instructions if you need to raise your TSH levels before a radioisotope scan.

Option 1
Have rhTSH (Thyrogen) injections

Option 2
Stop taking thyroid hormone replacement medicine

The synthetic drug known as rhTSH is a copy of the TSH produced by your body. It is often referred to by the brand name Thyrogen.
It is given as two injections, 24 hours apart.
You will have the radioisotope scan about 48–72 hours after your second rhTSH injection.
You don’t have to stop taking your thyroid hormone medicine.
rhTSH has few side effects, but some people experience headaches, nausea or weakness for a short time. Talk to your doctor for more information.

Prepare to stop taking your T4 hormone replacement medicine about 2–6 weeks before the blood test or radioisotope scan.
Once you stop, your TSH levels will increase but your thyroid hormone levels will decrease. This may cause hypothyroidism symptoms. Some people find it difficult to cope with this, while others don’t notice any difference.
Symptoms of hypothyroidism can be improved by taking T3 hormone replacement instead of T4. You can take T3 until 10–14 days before the scan. After this time, you stop all thyroid hormone replacement medicine until after the scan.

This information was last reviewed in January 2020. View who reviewed this content.

A/Prof Diana Learoyd, Endocrinologist, Northern Cancer Institute, and Northern Clinical School, The University of Sydney, NSW; Dr Gabrielle Cehic, Nuclear Medicine Physician and Oncologist, South Australia Medical Imaging (SAMI), and Senior Staff Specialist, The Queen Elizabeth Hospital, SA; Dr Kiernan Hughes, Endocrinologist, Northern Endocrine and St Vincents Hospital, NSW; Yvonne King, 13 11 20 Consultant, Cancer Council NSW; Dr Christine Lai, Senior Consultant Surgeon, Breast and Endocrine Surgical Unit, The Queen Elizabeth Hospital, and Senior Lecturer, Discipline of Surgery, University of Adelaide, SA; A/Prof Nat Lenzo, Nuclear Physician and Specialist in Internal Medicine, Group Clinical Director, GenesisCare Theranostics, and The University of Western Australia, WA; Ilona Lillington, Clinical Nurse Consultant (Thyroid and Brachytherapy), Cancer Care Services, Royal Brisbane Women’s Hospital, QLD; Jonathan Park, Consumer.

View the Cancer Council NSW editorial policy.

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