Asymptomatic Thyroid Dysfunction—Clinician FAQ

We recommend against screening asymptomatic non-pregnant adults aged 18 years of age and older for thyroid dysfunction (hyperthyroidism or hypothyroidism) in primary care settings (strong recommendation; low-certainty evidence).

This recommendation does not apply to adults who are pregnant or who have the following risk factors for thyroid dysfunction:

  • Previously diagnosed thyroid disease or surgery
  • Individuals receiving thyroid medications or medications that may affect thyroid function (e.g., lithium, amiodarone)
  • Previous or ongoing exposure to thyroid radioiodine therapy or head and neck radiotherapy
  • Individuals with pituitary or hypothalamic diseases

1. How is thyroid dysfunction identified?

  • Thyroid dysfunction is diagnosed based on abnormal levels of serum thyroid-stimulating hormone (TSH) and can be characterized as either hyperthyroidism or hypothyroidism.

2. How is screening defined?

  • Screening is routinely assessing patients who do not have any symptoms or a reason to believe they might have thyroid problems.

3. What is the rationale for a recommendation against screening?

  • Screening has potential harms, such as overdiagnosis of thyroid dysfunction, which can lead to additional testing and require clinical follow-up.
  • Diagnosis places a burden on the patient to fill medication for the rest of their lives and continually arrange for blood work (ranging from quarterly to annually).
  • No convincing evidence was found to support that screening asymptomatic non-pregnant adults confers increased clinical benefit over usual care.
  • Screening would consume resources without a demonstrated benefit.

4. Why is it a strong recommendation?

  • A strong recommendation implies that most individuals would be best served by the recommendation. Specifically, in this case, it means most asymptomatic individuals would be best served by no screening.

5. What are some considerations for implementing this recommendation?

  • If you do not routinely screen asymptomatic non-pregnant adults for thyroid dysfunction, there is no evidence-based reason to start.
  • If you do routinely screen asymptomatic non-pregnant adults for thyroid dysfunction, you should reconsider this practice given the finding that it is unlikely to be an effective preventive strategy in this population.
  • Remain alert to risk factors and symptoms suggestive of thyroid dysfunction and conduct appropriate diagnostic testing when warranted.