The prevalence of thyroid disease is approximately 10% in patients aged >50 years,¹ with an additional 3.6% with unrecognised thyroid dysfunction (abnormal thyroid-stimulating hormone [TSH]).² Autoimmune thyroid disease is the most common cause of thyroid dysfunction in Australia³ and 10–15% of the population have thyroid antibodies (more common in women than men).

Although early detection and treatment of people with thyroid disease may help prevent morbidity and mortality, screening and treatment of asymptomatic patients can result in harm due to overdiagnosis and overtreatment.

There is currently insufficient evidence to determine the benefits and harms of screening asymptomatic people for thyroid disease.⁴ Thyroid imaging is only indicated if there is concern regarding structural abnormalities.

Although iodine deficiency was previously reported in Australia, iodised salt in bread became mandatory in Australia and New Zealand in 2009, and iodine deficiency is now very rare.⁷

Primary congenital hypothyroidism is screened as part of Australia’s Newborn Bloodspot Screening program.

There are no additional recommendations for Aboriginal and Torres Strait Islander people.

Case finding tests may be appropriate in these populations where there may be a higher prevalence of thyroid dysfunction:^4,8

• people with associated conditions (type 1 diabetes, coeliac disease)
• Down syndrome
• family history of thyroid disease
• past history of thyroid disease
• symptoms or signs of thyroid dysfunction.

For GP and patient resources about thyroid tests (and information about subclinical hypothyroidism):
First do no harm: A guide to choosing wisely in general practice | RACGP