Is a TSH + Free T4 worth it?
What it costs, whether to test at home or at Quest or Labcorp, and how to read your results - reviewed and updated June 2026.
The short answer
Yes if you want a real thyroid answer in one draw rather than a bare screen. TSH tells you something is off; Free T4 tells you whether the thyroid gland itself is the cause - together they are the standard initial workup and save you a second visit if TSH comes back abnormal.
Who should order it (and who can wait)
Worth it if you...
- •Fatigue, weight change, hair thinning, cold intolerance, or mood changes
- •Irregular periods, a fertility work-up, or a family history of thyroid disease
- •Anyone whose TSH already came back abnormal and needs the next step now
- •A thorough thyroid baseline when you would rather not come back for a second draw
You can probably wait if you...
- •You just want the cheapest first screen and have no symptoms - a TSH alone is enough for most people
- •You suspect Hashimoto's or want the full picture - the Complete Thyroid Panel adds Free T3 and antibodies
We would rather you order the right test than the most expensive one.
At-home vs Quest vs Labcorp
The most common question we get. The short version: the lab and the result are the same - you are choosing where the blood is drawn.
Walk into a lab
Get drawn at any Quest or Labcorp location - thousands nationwide, often same-day. Best for speed and lowest cost.
At-home draw
A mobile phlebotomist comes to you, where available. Same venous sample, drawn at your kitchen table.
Same result
Whichever you pick, it is run on the same CLIA-certified analyzers with the same reference ranges.
This is a venous draw at Quest or Labcorp, or an at-home mobile draw where available - no fasting required. Try to be drawn around the same time of day if you are tracking changes, and if you take levothyroxine, draw before your dose or at least 4 hours after it so the level reflects your baseline.
How to read your results
The markers that matter most and what an out-of-range value can mean. Reference ranges vary by lab, age, and sex.
| Marker | Typical range | What it means |
|---|---|---|
| TSH | ~0.45-4.5 mIU/L | High usually means an underactive thyroid; low usually means an overactive thyroid. It is the more sensitive of the two markers. |
| Free T4 | ~0.8-1.8 ng/dL | The active hormone the thyroid puts out; reading it alongside TSH is what separates thyroid-gland problems from rarer pituitary ones. |
| The two together | Read as a pair | High TSH + low Free T4 = overt hypothyroidism; high TSH + normal Free T4 = subclinical (often watch and recheck); low TSH + high Free T4 = hyperthyroidism. |
Frequently asked questions
Ready to order your TSH + Free T4?
$27.99, physician-authorized, results in 1–3 business days. No insurance or doctor's visit required.
About this guide
Reviewed June 20, 2026. This is general health information, not medical advice, diagnosis, or treatment. Reference ranges vary by laboratory, age, sex, and clinical context - always interpret results with a qualified healthcare provider. Lab analysis is performed at CLIA-certified Quest Diagnostics and Labcorp facilities.