Thyroid Report: Normal Range & How to Read It
A thyroid report measures TSH, a signal from the pituitary gland, and the thyroid hormones T3 and T4. Your doctor reads them together.
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What a thyroid test checks
TSH
The signal that tells the thyroid how much hormone to make.
T3 and T4
The two main hormones the thyroid releases.
Free T3 and free T4
The part of each hormone that is free to act.
Thyroid normal range for adults
Labs differ a little. Always compare with the range printed on your report.
| Test | Normal range | Unit | What it tells you |
|---|---|---|---|
| Thyroid profile | |||
| TSH | 0.4–4.0 | mIU/L | High often means the thyroid is making less hormone. |
| Total T3 | 80–200 | ng/dL | The more active thyroid hormone. |
| Total T4 | 5.0–12.0 | µg/dL | The main hormone the thyroid releases. |
| Free hormones | |||
| Free T3 | 2.3–4.2 | pg/mL | T3 that is free to act. |
| Free T4 | 0.8–1.8 | ng/dL | T4 that is free to act. |
| Antibodies | |||
| Anti-TPO | Below 35 | IU/mL | Antibodies against the thyroid gland. |
Ranges from the NirogGyan biomarker library. Updated .
What a thyroid report looks like
The same results in the usual lab layout, and as a NirogGyan Smart Report.
Numbers and ranges in rows
Each value on our report slider
How to read your thyroid report
Check your details
Age, sex and pregnancy change the range that applies.
Find your result
The Result column shows your value for each test.
Compare with the range
The Range column shows what is normal for that test.
Look for H or L
A flag marks a value outside the range. Your doctor reads what it means.
Thyroid report questions
What is a normal TSH level?
Our biomarker library uses 0.4 to 4.0 mIU/L for adults. Labs and pregnancy ranges differ, so compare with your report.
What does a high TSH mean?
A high TSH often means the thyroid gland is making less hormone than the body needs. Your doctor reads it with T3 and T4.
What is the difference between T4 and free T4?
Total T4 counts all the hormone in the blood. Free T4 counts only the part that is free to act, so it is less affected by proteins in the blood.
Do I need to fast for a thyroid test?
Usually no. Some doctors prefer a morning sample so that repeat tests are done at the same time of day.
Are thyroid ranges different in pregnancy?
Yes. TSH targets are different in each trimester of pregnancy, and your doctor uses those ranges.
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Upload your reportThis page explains how to read a lab report. It does not replace advice from your doctor. All sample values are made up.