Thyroxine (T4) and Thyroid-Stimulating Hormone (TSH) Panel
Pairs the main thyroid screening hormone with circulating thyroxine to flag an under- or overactive thyroid.
Consider this test if:
- Fatigue, weight change, hair thinning, cold intolerance, or low mood with no clear cause
- Palpitations, heat intolerance, tremor, or unexplained weight loss
- Already taking levothyroxine or thyroid medication and checking your dose
- A family history of thyroid disease and wanting a baseline
- Irregular cycles, fertility planning, or symptoms during or after pregnancy
- HSA/FSA eligible
- Typical results in 1 day · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. Biotin supplements can distort thyroid immunoassays, so stop high-dose biotin for about 48 hours before the draw. If you take thyroid medication, note your dose and timing, since recent doses affect levels.
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What this test is for
This panel measures TSH, the pituitary signal that rises when the thyroid is underactive and falls when it is overactive, alongside total thyroxine (T4), the main hormone the thyroid releases. Together they show whether the thyroid is keeping output in range: a high TSH with low T4 points to hypothyroidism, while a low TSH with high T4 points to hyperthyroidism. It is commonly checked when investigating fatigue, weight change, cold or heat intolerance, hair thinning, constipation, palpitations, low mood, or irregular cycles, and it is also used to monitor people already on thyroid medication.
This version reports total T4, which includes hormone bound to carrier proteins and can read high or low when those proteins shift, as in pregnancy, estrogen use, or illness. If your TSH is abnormal and you want the unbound, active fraction, the separate Free T4 test is the usual follow-up.
Biomarkers tested
Includes 2 biomarkers
Total T4 measures all the thyroxine circulating in your blood, both the small free fraction that acts on cells and the larger portion bound to carrier proteins. Because binding proteins shift with pregnancy, estrogen, and liver or kidney conditions, total T4 can rise or fall without your actual thyroid function changing, which is why it's usually read alongside TSH and free T4 rather than alone. It's most useful for catching those binding-protein effects and rounding out the picture when TSH looks off but the cause isn't yet clear.
- Specimen
- Serum or plasma
- Measures
- Mass concentration
TSH is the pituitary's messenger to the thyroid, signaling it to produce more or less thyroid hormone based on what your body needs. This ultrasensitive assay (detection limit under 0.005 mIU/L) picks up even mildly suppressed levels, making it the sharpest tool for confirming hyperthyroidism and distinguishing it from a normal-low result. It's the marker to check when fatigue pairs with weight change, heat or cold intolerance, anxiety, racing heart, hair thinning, or irregular cycles, and it's just as useful as a baseline or for tracking thyroid medication dosing over time.
- Specimen
- Serum or plasma
- Method
- High-sensitivity assay
- Measures
- Concentration
What you'll learn
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Insights that connect the dots. A clinician reads your whole picture, not one result in isolation, connecting family history, past results, and lifestyle into clear next steps.
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Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
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Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
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Never miss a recheck. Mito tells you what is worth retesting and when, then reminds you so nothing slips.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 1 day
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost, covering the lab and what it takes to run the service. It is never a profit on the test itself. Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9 per month, and any applicable lab order or draw fee is itemized before you pay.
Where do I get tested?
Choose an available partner lab at checkout. If your cart contains multiple blood tests, Mito helps consolidate the eligible tests at one lab when possible. At-home kits and scans follow the collection or appointment process shown on their product page.
Is this eligible for HSA/FSA?
Yes. Eligible tests can be paid for with an HSA or FSA card at checkout.
When will I get my results?
Your results appear in your Mito dashboard after the laboratory completes processing. A clinician then reviews them before your analysis and personalized action plan are finalized. Timing varies by test, and specialty assays and at-home kits may take longer.
Do I need a physician's order?
No. Mito provides the laboratory order when one is required, so you do not need to arrange a separate physician visit before purchasing.
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