Thyroid Stimulating Hormone (TSH) with Free Thyroxine (FT4) and Free Triiodothyronine (FT3) Profile
This test measures key hormones involved in regulating your thyroid function, including thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). It helps assess whether your thyroid is working normally or if there may be an overactive or underactive condition.
["This panel helps diagnose and monitor thyroid disorders by checking hormone balance."]
Key facts at a glance
- LOINC
- 69561-9
- Short code
- TSH BldCo-aCnc
- Synonyms
- TSH BldCo-aCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 0.4
- Ref high
- 4
- Critical range
- 0.1 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84443
- SNOMED
- 301343003
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters for Your Health
Your thyroid gland produces hormones that control metabolism, energy levels, and many other bodily functions. If your thyroid isn’t working properly, it can lead to fatigue, weight changes, or other symptoms. This test helps doctors identify whether your thyroid is too active or too slow, guiding treatment decisions.
What Hormones Are Being Checked?
TSH (Thyroid-Stimulating Hormone) is produced by your pituitary gland and signals the thyroid to make more hormones. FT4 (Free Thyroxine) and FT3 (Free Triiodothyronine) are the active forms of thyroid hormones circulating in your blood. These three together give a full picture of your thyroid health.
When Might You Need This Test?
Doctors may order this test if you have symptoms like unexplained weight changes, fatigue, hair loss, or mood swings. It’s also used to monitor thyroid conditions like hypothyroidism or hyperthyroidism, especially after treatment for thyroid disorders.
What to Expect Before the Test
No special preparation is needed for this test. You’ll have a small blood sample drawn from a vein, usually in your arm. It usually takes about 15 minutes, and you can resume normal activities afterward. Avoid smoking or drinking alcohol for a few hours before the test if instructed.
Reference range
Adult: 0.4-4.0 mIU/LN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Thyroid Function Panel
Frequently asked questions
What does a ‘normal’ result mean for me?
Can I eat or drink anything before this test?
Will this test affect my medication?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy