t3 (eclia)
ThyroidBlood sampleResults 24 hrsNo fasting
T3 (ECLIA)
T3 (Triiodothyronine) is one of the main thyroid hormones that regulates your metabolism, heart rate, and energy levels. It is often checked alongside TSH and T4 to assess thyroid function, especially in suspected hyperthyroidism where T3 may be elevated.
Sample
Blood
Results
24 hrs
Fasting
Not required
Follow-up
Optional add-on
What this test detects
Total T3
ECLIA · serum
Quantitative (ng/dL)
When to get this test
Suspected hyperthyroidism
Helps confirm an overactive thyroid, where T3 levels are often raised, sometimes even when T4 is normal.
Unexplained symptoms
Useful when you have palpitations, weight loss, tremors, or heat intolerance that may point to a thyroid problem.
Monitoring thyroid treatment
Supports follow-up of patients being treated for thyroid disorders, alongside TSH and T4.
How to prepare
01
No special preparation needed.
02
If you take thyroid medication, ask whether to take it before or after the draw.
Common questions
Do I need to fast before a T3 test?
No, fasting is not required. You may eat and drink normally before your blood draw.
What is the difference between T3 and TSH?
TSH is the signal from your brain that tells the thyroid how much hormone to make, while T3 is one of the active hormones the thyroid produces. Doctors often look at them together to understand thyroid function.
When should I consider a T3 test?
It may be helpful if you have signs of an overactive thyroid such as a fast heartbeat, unexplained weight loss, tremors, or anxiety.