Thyroid hormone levels should be checked regularly to monitor thyroid function and adjust treatment as needed. The frequency of testing depends on several factors.
For healthy individuals
For people without thyroid disease, there are no formal recommendations for routine thyroid testing. However, thyroid hormone levels may be checked as part of an annual physical exam or standard bloodwork panel.
Some medical organizations recommend baseline thyroid testing at age 35, with repeat testing every 5 years. More frequent testing may be done for people at higher risk of developing thyroid problems, such as those with a family history of thyroid disease.
For those being treated for hypothyroidism
People taking thyroid hormone replacement medication for hypothyroidism need to have their thyroid levels monitored regularly to ensure the dose is adequate. Testing is typically recommended:
- 4-8 weeks after starting medication or after a dose change
- Every 6 months once the optimal replacement dose is determined
- Annually after thyroid levels have stabilized
More frequent testing may be needed if symptoms persist or medication needs are changing. Thyroid levels may also be checked after changes in body weight, during pregnancy, and with certain medications.
For those being treated for hyperthyroidism
People receiving treatment for hyperthyroidism need regular testing to assess response to therapy. Testing frequency depends on the treatment method:
- Every 4-6 weeks when starting antithyroid medication
- Every 3 months once dose is stabilized
- Every 6-12 months for several years after radioactive iodine therapy
- Every few months after thyroid surgery
Doctors also monitor thyroid levels in hyperthyroid patients when making changes to treatment dose or approach.
For monitoring thyroid nodules or goiter
If a thyroid nodule or goiter is detected, thyroid tests may be done more frequently to monitor for changes. This includes TSH, thyroid hormones, and imaging studies in some cases. Testing every 6-12 months is common, but depends on nodule characteristics.
During pregnancy and postpartum
Thyroid hormone needs increase during pregnancy, so TSH should be checked:
- At the start of prenatal care
- Each trimester
- 6-12 weeks postpartum
Testing may be done more often if abnormal thyroid levels are found or a woman has symptoms or risk factors for thyroid problems.
When thyroid symptoms are present
Thyroid testing should be done whenever a person develops potential symptoms of too much or too little thyroid hormone, such as:
- Fatigue
- Weight changes
- Hair loss
- Irregular periods
- Constipation or diarrhea
- Muscle weakness
- Changes in heart rate
Conclusion
In summary, thyroid function tests are recommended:
- Every 5 years starting at age 35 for general screening
- Every 4-12 months for monitoring thyroid disorders
- During pregnancy and after delivery
- Whenever thyroid-related symptoms are present
Doctors may order thyroid tests more frequently depending on a person’s symptoms, medical history, medications, and other factors. Ongoing testing is important for guiding thyroid disorder treatment and detecting changes in thyroid status over time.