Early detection matters. Learn how to decide if you should get tested for thyroid disorders.

Screening for thyroid dysfunction

The best screening test to check if the thyroid gland is functioning normally is the thyroid function blood test. TSH is very sensitive to fluctuations in thyroid hormone levels. A change in TSH level may be an early warning sign before actual thyroid abnormalities occur.¹

Routine screening for hyperthyroidism or hypothyroidism is generally not recommended if you do not have symptoms as this can lead to false diagnosis and overtreatment.² In Singapore, the thyroid function test is considered a Category 2 screening test. This means that screening for thyroid disorders is beneficial to high-risk groups but not to the general population.³

The need for screening depends on whether certain risk factors are present. The Ministry of Health recommends screening for thyroid disorders in the following high-risk groups:

• People who are obese (body mass index ≥30 kg/m²)^3,4

Hypothyroidism may be a symptomatic in obese persons. A thyroid function test can be done just once when investigating the cause for obesity.  

• People with autoimmune disease³

People with autoimmune disease are predisposed to Graves’ disease and Hashimoto’s thyroiditis. TSH levels should be assessed annually.

• Pregnant women with diabetes or adrenal disease³

There is a greater risk for developing goitre during pregnancy. In addition, thyroid dysfunction during pregnancy has serious consequences on brain development in the child.
A thyroid function test should be performed once during the early stage of pregnancy.

Type 1 diabetes is commonly associated with autoimmune thyroid disease. Screening is recommended for children and adolescents with type 1 diabetes at diagnosis and annually thereafter.⁵

Screening for thyroid cancer

Thyroid cancer screening by manual neck examination or ultrasound scan is not recommended for the general population, as such screenings may do more harm than good.⁶

Thyroid cancer screening is strongly encouraged in patients who have risk factors or show signs and symptoms that warrant further investigation⁷ .
Risk factors for thyroid cancer include:

• Women – thyroid cancer affects more women than men⁸
• A family history of thyroid cancer⁷
• Exposure to high levels of radiation to the head and neck region (e.g., radiation therapy)⁷
• Certain inherited genetic conditions that increase risk of thyroid cancer, such as familial medullary thyroid cancer, multiple endocrine neoplasia, Cowden’s syndrome and  familial adenomatous polyposis⁷

All patients with a thyroid nodule detected by manual neck examination should undergo an ultrasound scan. Nodules with suspicious ultrasound features may require additional diagnostic tests, such as a fine-needle aspiration biopsy, to determine their potential malignancy.⁷

Screening for congenital hypothyroidism

Congenital hypothyroidism (CH) is a condition where babies are born with thyroid hormone deficiency. This may be due to an absent, underdeveloped or poorly functioning thyroid gland.⁸ About 1 in 3000 newborns are affected by CH.¹⁰

Babies who are born with CH generally do not have obvious symptoms at birth.¹⁰ All newborn infants in Singapore will receive screening for CH. This is done by measuring TSH levels using blood samples taken from the umbilical cord. If the cord blood TSH level is abnormal, a repeat blood test will be done to confirm thyroid status.³

CH is one of the most common preventable cause of intellectual disability. Once a diagnosis has been made, treatment will be started 2-4 weeks of birth to support the baby’s brain development.¹⁰

Summary

• Routine screening for hyperthyroidism or hypothyroidism is recommended for high-risk groups and not for the general population.
• Thyroid cancer screening is strongly encouraged in patients who have risk factors or show signs and symptoms that warrant further investigation
• All babies born in Singapore are screened for congenital hypothyroidism.