When should I take T3 prior to a blood test?

[janeroar]

I have to do follow up blood tests since starting in combination of T3 and T4 medication.

I am currently taking 100mg T4 and 20 mg T3 at 630am and another 10mg T3 at 6pm.

I know the advice here is to avoid taking thyroxin before a test but my doctor said I should take a dose of t3 three hours before test to check how much is being utilised.

Not sure about getting up in middle of night or should I delay the test til mid morning so I can take my medication at normal time but presumably this will affect result of TSH levels too.

Thanks ever so much all for your good advice here.

[SeasideSusie Remembering]

janeroar

T3 peaks in the blood 2-4 hours after ingesting. So your doctor's suggestion of taking your T3 just 3 hours before your test will ensure your FT3 is at it highest, and that will enable him/her to say that you are overmedicated with T3.

T3 is no longer detectable in the blood after 12 hours.

The best time to take T3, to show a normal circulating result, is 8-12 hours before a blood test.

If I were you, for the day before your blood test, I would alter the timing of my T3 and take the evening dose later - maybe bedtime - depending on the time of your blood test.

[janeroar in reply to SeasideSusie]

Ok so will take at bedtime. Thanks so much.

[MaisieGray]

"my doctor said I should take a dose of t3 three hours before test to check how much is being utilised" - if he can conclude that, then he should patent his method, as no one else can do it! Blood levels are just that - blood levels, and Free T3 levels indicate how much free hormone ie unbound from its protein carrier, is available for use, but not what is being utilised, ie in the cells.

[janeroar in reply to MaisieGray]

Well I think the advice here is nearly always more informed. Thanks so much.

[janeroar]

Really appreciate thanks v much for your response.

[SlowDragon Administrator]

Advice on here (and by my own endo) is 12 hours prior to test

So delay 6pm T3 dose until 9pm night before and get bloods at 9am

[janeroar in reply to SlowDragon]

Fantastic thanks Slow Dragon. Glad your endo is more informed. Is she/he in France?

[SlowDragon Administrator in reply to janeroar]

No, in UK

Just probably aware there's too much reliance on blood test results over patient's reduction in symptoms