T3 and T4 (Total)
The two circulating thyroid hormones, measured alongside TSH to confirm an over- or under-active thyroid.
Also known as: T3, T4, triiodothyronine, thyroxine
Price on request
We can collect this sample at your home, free of charge. Book a home visit.
- Turnaround
- Same day
- Preparation
- No fasting needed. Eat and drink normally.
- Sample
- Blood sample
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About this test
TSH tells you the pituitary's opinion of your thyroid; T3 and T4 tell you what the thyroid is actually producing. The pair is ordered when a TSH result is abnormal, to separate a genuinely over- or under-active gland from a pituitary problem, and to grade how far from normal it is.
What it measures
- Total triiodothyronine (T3)
- Total thyroxine (T4)
A note on results. A single test is one part of a clinical picture, not a diagnosis. Discuss your report with a qualified doctor, who will read it alongside your history and examination.
Related to
- Thyroid
Often ordered with this
Anti-TPO Antibodies
Identifies autoimmune thyroid disease as the cause of an abnormal thyroid result.
- 24–48 hours
- No fasting
- Home collection
Free T3 and Free T4
The unbound, biologically active fraction of the thyroid hormones.
- Same day
- No fasting
- Home collection
Thyroglobulin
Used to monitor for recurrence after treatment for thyroid cancer.
- 3–5 working days
- No fasting
- Home collection