FT3 normal range — check your value
Roughly 2.0 to 4.4 pg/mL, though the range differs noticeably between labs and methods.
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Which test?
Type the test name printed on your report (SGPT, TSH, Vitamin D).
About you
Your FT3 test value
Copy it exactly as printed in your report
What FT3 measures
The active, unbound form of triiodothyronine, the thyroid hormone that acts directly on body tissues.
FT3 normal range chart
These bands are for female, 31–45 years. Enter your age and gender above to see the bands for you. The table below shows the range for every age and gender.
FT3 normal range by age and gender
What a high FT3 means, and common causes
The active thyroid hormone is above range, which fits an overactive thyroid when TSH is also low.
Common causes: Graves' disease, a toxic nodule, thyroiditis, excess thyroid medication, and T3 toxicosis where T3 rises before T4 does.
What a low FT3 means, and common causes
Free T3 is below range. In unwell patients this is often not a thyroid problem at all.
Common causes: Hypothyroidism, and very commonly non-thyroidal illness, where serious illness, starvation or surgery lowers T3 without any thyroid disease being present.
Frequently asked questions
Please note. This page explains what a number means against reference ranges for your age and gender. It does not diagnose anything, cannot see the rest of your report, and is no substitute for a doctor. If your lab’s printed range differs, your lab’s range applies.