âī¸ Written by the MedTestBD Editorial Team ¡ Last reviewed: June 2026
What is the T3 Test?
The T3 test measures the level of triiodothyronine â one of the two main hormones produced by the thyroid gland. T3 plays a key role in regulating your metabolism, heart rate, body temperature, and energy levels. It is usually ordered alongside TSH and T4 tests to get a complete picture of thyroid function.
Why is the T3 Test Done?
- To diagnose hyperthyroidism (overactive thyroid) â T3 is often elevated even when T4 is normal
- To investigate symptoms like rapid heartbeat, unexplained weight loss, sweating, or anxiety
- To monitor patients already on thyroid treatment
- To evaluate a condition called T3 toxicosis, where only T3 is elevated
- To complete a full thyroid panel alongside TSH and Free T4
Normal T3 Levels
| Type | Normal Range |
|---|---|
| Total T3 (adults) | 80 â 200 ng/dL (1.2 â 3.1 nmol/L) |
| Free T3 (adults) | 2.3 â 4.2 pg/mL (3.5 â 6.5 pmol/L) |
High T3 usually indicates an overactive thyroid or excessive thyroid hormone supplementation. Low T3 can indicate an underactive thyroid or severe illness. Results must always be interpreted alongside TSH and symptoms.
How to Prepare for the T3 Test
- No fasting is required for this test
- Inform your doctor about any thyroid medications, steroids, or hormone therapy you are taking
- If you take biotin supplements, your doctor may advise stopping them 24â48 hours before the test as biotin can interfere with thyroid test results
- A simple blood sample is collected from a vein in your arm
T3 Test Price in Bangladesh
T3 test prices vary between diagnostic centers across Bangladesh. Compare T3 test prices on MedTestBD â
â ī¸ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.