Thyroid Hormone Profile with Free T4 and TSH Measurement
This test measures key hormones related to your thyroid function, including thyroid-stimulating hormone (TSH) and free thyroxine (T4). It helps assess whether your thyroid is working properly.
["This test helps diagnose and monitor thyroid disorders like hypothyroidism or hyperthyroidism."]
Key facts at a glance
- LOINC
- 69202-0
- Short code
- MR Guided Thyroid Bx
- Synonyms
- MR Guided Thyroid Bx
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- mr
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
Your blood sample will be analyzed for two primary thyroid-related hormones: **thyroid-stimulating hormone (TSH)**, which signals the thyroid to produce hormones, and **free thyroxine (T4)**, the active form of thyroid hormone circulating in your blood. These measurements help determine if your thyroid is producing too much or too little hormone.
Why It’s Done
Doctors may order this test if you have symptoms like fatigue, weight changes, unexplained hair loss, or if you’ve been diagnosed with a thyroid condition. It’s also used to monitor thyroid treatment progress or screen for thyroid issues before surgery or during pregnancy.
Sample Collection and Preparation
A small blood sample will be drawn from a vein in your arm. You may feel a brief pinch, but it’s usually over quickly. No special preparation is needed, though fasting may be advised for some related thyroid tests—always follow your healthcare provider’s instructions.
What to Expect After the Test
After your blood is drawn, you can resume normal activities immediately. Results will be reviewed by your healthcare provider, who will discuss them with you during a follow-up visit. Results may take a few days to weeks to process, depending on lab schedules.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal results can indicate thyroid dysfunction. For example, high TSH with low free T4 often signals **hypothyroidism** (underactive thyroid), while low TSH with high free T4 suggests **hyperthyroidism** (overactive thyroid). These findings can guide treatment, such as hormone replacement or medication adjustments, to restore balance and alleviate symptoms.
Short name
Thyroid Function Test
Frequently asked questions
How long does it take to get my results?
Do I need to fast before this test?
Can I take my thyroid medication on the day of the test?
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