Thyroid Blood Test
The standard thyroid test performed in Australia is a thyroid function test. Thyroid function tests are measured by a thyroid blood test and the Medicare protocol for screening patients who have not yet been diagnosed with a thyroid function problem is to test TSH first and only if the result of this test is outside the reference range then to test Free T4
A thyroid test may include:
Thyroid Stimulating Hormone – TSH
Free Thyroxine (Free T4 or FT4)
Free Triiodothyronine (Free T3 or FT3)
Thyroid Antibodies
Thyroglobulin
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Thyroglobulin antibodies are the antibodies to the major component of thyroid colloid and precursor of thyroid hormones.
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These are found in most people with Grave’s disease and nearly all with Hashimoto’s thyroiditis.
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Thyroglobulin antibodies are also used as a marker to detect residual or recurrent tumour in patients who have undergone treatment for differentiated thyroid cancer.
Thyroid peroxidise (TPO)
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Antibodies to thyroid peroxidise are found in most patients with Grave’s disease or Hashimoto’s thyroiditis.
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Raised titres of thyroid peroxidise are also found after childbirth and in autoimmune diseases such as rheumatoid arthritis.
Thyroid stimulating hormone receptor antibodies (TRAbs)
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Most TSH receptor antibodies have a thyroid stimulatory action
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In some instances TRAbs bind to the receptor and block activity
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Measurement of TRAbs is helpful in the diagnosis of Grave’s disease, being detected in 90% of patients
Calcitonin
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Increased serum levels of calcitonin are found in medullary thyroid cancer (MTC)
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Calcitonin levels may be used for screening in people with thyroid nodules
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Calcitonin levels are used to assess the completeness of surgical treatment for patients with MTC and are valuable in follow-up
Carcinoembryonic antigen (CEA)
- CEA measurement is a helpful adjunct to calcitonin in the follow-up of patients with MTC
If you have any questions about getting a thyroid test, thyroid or parathyroid surgery, you should speak to your local doctor, who will arrange to contact your thyroid surgeon.