Ordering the TSH Free T3 and Free T4 Panel
The TSH Free T3 and Free T4 Panel helps check how well your thyroid is working by measuring thyroid-stimulating hormone (TSH), unbound triiodothyronine (Free T3), and unbound thyroxine (Free T4) in your blood. These markers can show if your thyroid is making too much or too little hormone, which can affect your energy, weight, and how your body uses food. Interestingly, Free T3 and Free T4 levels can sometimes show thyroid changes before TSH levels shift, giving an early look at possible thyroid issues.
Ordering this panel can help you:
- Spot early thyroid changes before symptoms become noticeable
- Track how well thyroid treatment is working
- Find out if unexplained tiredness or weight changes are linked to your thyroid
- Check for thyroid problems if you have a family history of thyroid disease
- Monitor thyroid function if you have an autoimmune condition
Who Might Benefit from Thyroid Function Blood Work
People who feel tired all the time, have trouble losing or gaining weight, or notice changes in their hair or skin may want to check their thyroid. For example, someone who feels unusually cold even in warm weather and has noticed their hair thinning might want to know if their thyroid is involved.
Ordering this panel may also be helpful in these situations:
- Someone with a family member who has thyroid disease
- People with type 1 diabetes or other autoimmune conditions
- Those who have had neck surgery or radiation in the past
- Women who are pregnant or planning to become pregnant
- Someone who has trouble with memory or focus, which can sometimes be linked to thyroid changes
Checking these markers can help you find out if your thyroid is causing symptoms like tiredness, weight changes, or mood shifts. Delaying this panel could mean missing early signs of thyroid changes, which might make it harder to manage symptoms or adjust treatment plans.
Preparing for Your Thyroid Hormone Panel
Fasting is not needed for this blood test, so you can eat and drink as usual before your appointment. Always follow any instructions your doctor or healthcare provider gives you, as they may have specific guidance based on your situation.
Labs Included When Ordering Your TSH Free T3 and Free T4 Panel
| Test Name | Reference Range | What This Marker Shows | Low and High Levels of This Marker |
|---|---|---|---|
| TSH 3rd Generation | 0.40 – 4.50 | TSH, or thyroid-stimulating hormone, is made by the pituitary gland and tells the thyroid to make hormones. It helps keep thyroid hormone levels balanced in your body. |
High levels mean your thyroid may not be making enough hormone (hypothyroidism).
Low levels mean your thyroid may be making too much hormone (hyperthyroidism). |
| Unbound (free) T3 | 2.3 – 4.2 | Free T3 is the active form of triiodothyronine that is not attached to proteins in your blood. It helps control how your body uses energy and affects many body systems. |
High levels mean your thyroid may be overactive (hyperthyroidism).
Low levels mean your thyroid may be underactive (hypothyroidism). |
| Unbound (free) T4 | 0.8 – 1.8 | Free T4 is the main form of thyroxine that is not bound to proteins, showing how much hormone is available for your body to use. It helps control metabolism and energy use. |
High levels mean your thyroid may be making too much hormone (hyperthyroidism).
Low levels mean your thyroid may not be making enough hormone (hypothyroidism). |
Reference ranges can change over time. For the most current values, visit the Quest Diagnostics lab test directory.
TSH Free T3 and Free T4 Panel FAQ
Is there TSH Free T3 and Free T4 Panel testing near me?
You can find a nearby location for TSH Free T3 and Free T4 Panel blood work using the patient service center locator, which also lists mobile phlebotomy options. This makes it easier to get tested if you have symptoms like tiredness or weight changes and need a convenient place for sample collection.
What is the cost of the test?
The price you see for the TSH Free T3 and Free T4 Panel covers everything, including the blood draw at a patient service center. Ordering this panel is worth it if you want to find out if your thyroid is causing symptoms like tiredness or changes in weight.
How often should I retest?
Most people retest every 6 to 12 months, or as recommended by their doctor, especially if they are starting or changing thyroid treatment. Regular retesting helps track how your thyroid levels respond to treatment and can show if any adjustments are needed.
How accurate is the test?
This panel uses immunoassay methods for TSH, Free T3, and Free T4, which are known for high precision. The specificity is 99.5% and the sensitivity is 99.2%. All tests at TrueHealthLabs.com are performed by CLIA-certified labs, meeting strict quality and precision standards.
Medical Review Board
Reviewed by Jeff Donohue M.D. from Body Logic and Brady Hurst DC, CCCN. Written by True Health Lab’s team of editorial health contributors.
Disclaimer: This information is for educational purposes only and not intended as medical advice. Consult your healthcare provider for personalized guidance.
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