Blood tests
Blood tests help evaluate thyroid function. Results need to be interpreted with the reason for testing, symptoms, medicines, and medical history.
Patient education
Testing and Diagnosis
Thyroid evaluation may involve blood tests, imaging, or sometimes a biopsy. The appropriate next step depends on why testing was ordered and how the results fit together.
Patient guides
Detailed guides available now
Start with the guide that matches the test or procedure you want to understand.
Thyroid Blood Tests
How TSH, free T4, T3, and thyroid antibody results are interpreted together.
Read the patient guideThyroid Ultrasound
What the exam shows, how reports describe nodules, and what TI-RADS means.
Read the patient guideUltrasound-Guided Thyroid FNA Biopsy
What to expect before, during, and after a fine-needle aspiration biopsy.
Read the patient guideThyroid Uptake Test and Scan
How uptake testing and thyroid scans are used in selected situations.
Read the patient guideHow testing fits together
One result rarely tells the whole story.
A clinician may consider symptoms, medical history, examination findings, medicines, blood-test results, and imaging before deciding whether another test is useful.
Thyroid ultrasound
Ultrasound describes thyroid structure, nodules, and nearby lymph nodes. It does not measure thyroid hormone function.
Biopsy and cytopathology
Fine-needle aspiration collects cells when a nodule meets clinical and ultrasound criteria for sampling.
Nuclear medicine tests
An uptake test or scan may help answer selected thyroid questions, including some causes of hyperthyroidism.
Related conditions
See testing in the context of a diagnosis.
Condition guides explain why different tests may be considered and how results can affect the next step.
Thyroid Nodules
See how ultrasound and biopsy may be used to evaluate a thyroid nodule.
Read the guideHypothyroidism
Learn how blood tests help confirm an underactive thyroid.
Read the guideHyperthyroidism
Understand how laboratory and nuclear medicine tests may help identify the cause.
Read the guideThyroid Cancer
Review the role of ultrasound, biopsy, pathology, and follow-up testing.
Read the guideSources and medical review
Earlier versions of Thyroid.com included separate sections on thyroid laboratory testing, nuclear testing, diagnostic ultrasound, and cytopathology. The linked patient guides explain these tests using current clinical guidance.
This overview and the linked testing guides have been medically reviewed by Richard B. Guttler, MD, FACP, FACE, ECNU. Supporting sources are listed in each guide.