Thyroid Blood Testing
Thyroid Blood Testing is a laboratory test you can order directly. Thyroid blood testing measures how well your thyroid gland is working. It is ordered to check for an underactive or overactive thyroid, to monitor thyroid treatment, or to investigate symptoms like fatigue, weight change, or palpitations.
- Sample type
- blood
- Category
- Thyroid
- Turnaround
- 1-3 business days
- Price
- $39
- Referral
- Not required
Thyroid blood testing measures how well your thyroid gland is working. It is ordered to check for an underactive or overactive thyroid, to monitor thyroid treatment, or to investigate symptoms like fatigue, weight change, or palpitations.
What it measures
- TSH (thyroid-stimulating hormone) — A pituitary hormone that tells the thyroid to work harder; it is often the first test used to screen for thyroid problems.
- Free T4 (thyroxine) — The main thyroid hormone available to your body; low or high levels help show whether the thyroid itself is underactive or overactive.
- Free T3 (triiodothyronine) — The active form of thyroid hormone; it may be checked when TSH and free T4 do not fully explain symptoms.
- Thyroid peroxidase (TPO) antibodies — Proteins that can attack the thyroid; their presence may suggest an autoimmune cause of thyroid problems.
Who it is for
A primary care clinician, endocrinologist, or other healthcare provider typically orders thyroid blood testing. It may be ordered for routine screening, symptom evaluation, or monitoring of thyroid medication.
Preparation
No fasting is usually required for thyroid blood tests. Tell your clinician about all medications and supplements you take, because some can affect results; timing may matter if you take thyroid hormone.
Results and what they mean
Results are reported as numbers with a reference range, and your clinician interprets them alongside your symptoms, history, and other tests. A result outside the reference range does not by itself mean you have a thyroid condition. This is general information, not medical advice; discuss your results with a qualified clinician.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the thyroid blood testing is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast before a thyroid blood test?
Usually no. Fasting is not typically required, but follow any specific instructions from your clinician.
How long does it take to get thyroid test results?
Most thyroid blood tests are reported within 1 to 3 business days, though this can vary by laboratory.
Can medications affect my thyroid test results?
Yes. Some medications and supplements can change thyroid hormone levels or test results, so tell your clinician what you take.
What if my TSH is abnormal but my other thyroid tests are normal?
That pattern can have several explanations. Your clinician will consider your symptoms and may repeat or add tests to clarify.