Understanding results

[paul1978]

Hi what is serum free triiodothyronine level ?

T3?

[MaisieGray]

It is the same as serum FREE T3.

[paul1978]

Do you get symptoms if your T3 is high

[greygoose in reply to paul1978]

Depends how high. And is your high FT3 from taking T3 replacement? Or because you have Grave's or Hashi's?

[paul1978 in reply to greygoose]

No levo.

Ft3 was 6.7

I have no thyroid

[greygoose in reply to paul1978]

If you have no thyroid, you must be taking something.

I'm afraid we need a range with that result, or we cannot tell how high it is.

[paul1978 in reply to greygoose]

Hi.

I am taking 200mcg of levo thyroxin

Range is 3.8-6.2

[greygoose in reply to paul1978]

But, above you said 'no levo'. I'm confused!

Your FT3 is a little over-range, but nothing to worry about. I wouldn't expect it to give you much in the way of symptoms. What sort of symptoms do you have?

[anonymous45]

Triiodothyronine is the name for T3, also known as Liothyronine when given as a medicine.

Serum refers to the component of the blood that transports most molecules in the body.

Free simply means it is not bound to protein in the blood, bound molecules are considered inactive until unbound. The free portion is the unbound and thus active hormone fraction.

Serum Free Triiodothyronine is therefore the active (unbound) T3 contained in your blood. It is a good marker of active thyroid hormones in the body, since it controls metabolism etc. more directly than Thyroxine (T4), which first must be converted to T3 in the liver, Thyroid, or other tissues of the body.

[Angel_of_the_North]

It is the level of the active thyroid hormone - the one that defines how well we feel.

[SlowDragon Administrator]

Looking at your previous posts, you recently had dose of Levothyroxine increased

Bloods should be retested 6-8 weeks after each dose increase

How are your vitamin levels?

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. Do not take Levothyroxine dose in the 24 hours prior to test, delay and take immediately after blood draw. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?