How Thyroid Is Tested: TSH, T3, T4 & What They Mean
Thyroid is tested with blood work: TSH is the primary screening test, T4 and T3 measure actual hormone levels, and thyroid antibodies (TPO, TgAb) detect autoimmune thyroid disease. A full panel gives the most complete picture.
Understanding thyroid tests
Each test tells a different part of the story.
- TSH: high means underactive thyroid; low means overactive.
- Free T4 and Free T3: the actual hormones your body uses.
- TPO and TgAb: antibodies that indicate Hashimoto's or Graves' disease.
- Reverse T3: sometimes ordered to assess thyroid hormone conversion.
Track how you feel and spot the pattern
PhaseBloom logs your symptoms and mood against your cycle in seconds a day, so you can see which days hit hardest and prepare before they arrive.
Track how you feel and spot the pattern
PhaseBloom logs your symptoms and mood against your cycle in seconds a day, so you can see which days hit hardest and prepare before they arrive.
Frequently asked questions
Is TSH enough to test thyroid?
TSH is a good screening test, but it does not tell the whole story. If you have symptoms despite normal TSH, ask for Free T4, Free T3, and antibodies to get a fuller picture.
What does high TSH mean?
High TSH means your pituitary is signaling your thyroid to work harder, which usually indicates hypothyroidism (underactive thyroid).