T3 blood test - 4 hrs after taking?

[HotelHurricaine]

Hello there,

I’ve been working on getting myself to feel well with the help of this forum for a few years, and most productively in the last 14 months.

Vitamin D, B12, Folate, Ferritin all at optimal levels.

Was taking 137.5mcg Levo.

Was still a poor converter so saw private endo Feb who prescribed 5mcg T3.

For last 6 weeks have been taking 137.5mcg levo plus 5mcg T3.

Blood tests taken last Tuesday as per this forums advice.

Today, endo has sent me for 2nd blood test as he says T3 needs to be tested 4 hrs after taking (and not 12 hrs as I had done) in order to see its peak level.

I’m doing this now, just wondered what people here thought?

I will add that since taking 5mcg T3 my FT4 has gone down and my T3 has gone down and I have been feeling terrible. Endo will now be prescribing based on tests done this morning when I’ve taken T3 this am and T4 last night.

[humanbean]

Today, endo has sent me for 2nd blood test as he says T3 needs to be tested 4 hrs after taking (and not 12 hrs as I had done) in order to see its peak level.

I suspect that your dose of T3 will be reduced (or, worse still, taken from you altogether) if the Free T3 is above range 4 hours after it is taken. Even worse would be if he tested Total T3 and used that as his guide.

I do have some large gaps in my honesty when it comes to doctors because I don't trust them at all. So my reaction would be to only take half of your T3 dose before the test, and just keep that to yourself, and keep your fingers crossed that your result keeps the endo happy.

By checking to see the peak level of your T3 just fours hours after you've taken it, it seems likely that your endo is determined that your level be within the range for a full 24 hours. But by reducing your dose he will probably just ensure that your T3 level is low for a big proportion of each 24 hour period.

[HotelHurricaine in reply to humanbean]

Thank you humanbean that was what I feared. He’s looking at dates and times of blood test and I’ve already taken todays T3 so can’t split it!

Last week my FT3 was 4.0 (3.1-6.8) - previous test was 4.7(3.1-6.8)

FT 15.3 (12-22) - previous test was 19.2(12-22)

On 5mcg T3.

So he can’t reduce my T3 but he might not put it up as I’d hope he would.

[SlowDragon Administrator in reply to HotelHurricaine]

Endo will now be prescribing based on tests done this morning when I’ve taken T3 this am and T4 last night.

Last dose levothyroxine should have been 24 hours before test

If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test

If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning. Delay Sunday evening dose levothyroxine until after blood test on Monday morning. Take Monday evening dose levothyroxine as per normal

Do you normally leave 24 hour gap?

5mcg T3 unlikely high enough dose. But will have lowered TSH and Ft4 dropped……

Get 2nd dose T3 added

And you may need to increase Levothyroxine after next test

[HotelHurricaine in reply to SlowDragon]

Thanks SlowDragon I normally take all tests as per this forum's guidance ie levo 24 hrs prior, T3 12hrs prior but he has just scuppered that!

May I ask is it common for both FT4 and FT3 to lower when first add T3?

It explains why I have been feeling so dreadful, but I hope its all correctable by raising levo and T3.

I was hoping to be raised to 150 mcg levo and 10 mcg T3 and now await results of today's (surprise) blood test before prescription.

[SlowDragon Administrator in reply to HotelHurricaine]

Your Ft4 has reduced a lot, especially considering Levo dose wasn’t reduced

We do frequently see Ft4 drop

I would agree you probably want to experiment with increasing levothyroxine

[HotelHurricaine in reply to SlowDragon]

Thank you for replying SlowDragon .

Would you recommend raising one at a time rather than both together?

I feel much better on 150mcg levo even after 1 week. Unsure if adding any more T3 at this stage is a good idea or not.

Awaiting endo instructions but would appreciate your thoughts.

[HotelHurricaine in reply to SlowDragon]

Attached results 14 hrs post 150 mcg levo, 4 hrs post 5 mcg T3

results

[SlowDragon Administrator]

yes only increase one at a time

So wait 6-8 weeks after increasing levothyroxine and retest

[HotelHurricaine in reply to SlowDragon]

Thank you SlowDragon