Inconsistently high FT4 reading

[ak_83]

I'm hypothyroid Hashimoto’s male and have been tweaking my T4 + T3 combo for awhile now and for the last four months I've been on 150T4 + 15T3.

I've just got the FT4 / FT3 / TSH blood test, which showed a very high FT4 = 24.8 (range: 12 - 22).

I've previously been on 150T4 + 15T3 for 5 weeks with FT4 = 18 and other combos of T3 with 150T4 showing FT4 =19.

I'm really perplexed about it as I thought I was in a good place as far as T4 goes. T4 is supposed to be the steady one compared to the T3! I'm now not sure if this level will stay like this or will revert back to the previous measures. As it stands I need to cut back on T4 significantly. I'm thinking 125T4 at least, maybe even 100T4, both of which are historically too low in the tests.

I haven't changed what thyroid brand I take. The time of day has stayed consistent for years now too - 6am, which is at least 1.5 hours before breakfast to ensure full absorption with the type food etc not being a factor.

One thing I can think of is I haven't been on 150T4 for this long before ~18 weeks. Did it just accumulate? I thought after 6-8 weeks the FT3 levels are stable.

The other thing is I've been on a reset diet for 4 weeks, which removes added sugars, caffeine (was drinking one barrister flat white coffer per day) and alcohol. So basically removed the junk and left the healthy stuff in. Didn't think this would change absorption levels as I always take the meds 1.5 hours before the first meal of the day (and any coffee etc) so the intake of sugar / coffee / milk (factors that I understand can change absorption of T4) would be very far away from the dose inyake. The T4 would be in the blood ~ 30-60 minutes after. After 1.5 hours there should be nothing at all left to interfere with - all in the blood stream (I thought). 4 more weeks of this to diet to go.

Something is not adding up here. Anyone had this happen? Any explanations or ways to "fix" it?

[Yeswithasmile]

Hi ak…

Just for clarity what time do you take your bloods? Is it always the same time and do you take levo and t3 before you bloods or do as recommended on here?

Just thought this extra info might help everyone try an assist you 😊

[ak_83 in reply to Yeswithasmile]

Yes, of course, I have my methodology down pat, I believe as recommended here.

I take my bloods in the morning before breakfast before 9am. At that stage my last T4 dose is ~24 hours ago and my T3 dose is ~12 hours ago.

[greygoose]

You have Hashi's, so it's not surprising if levels jump around a little. Do you know how Hashi's 'works'?

[ak_83 in reply to greygoose]

I understood that with Hashimoto’s the body can intermittently have thyroid antibodies attack. However, I thought this affected TSH levels, where they can jump around at those times.

However, I thought that when I am on full replacement T4 (and T3), those levels (and their absorption) should not be affected by the antibodies as they affect thyroid tissue, which by now I would not have much left to destroy.

Am I missing something?

[greygoose in reply to ak_83]

I'm afraid you're missing quite a lot, yes.

TPO and Tg antibodies - the antibodies that indicate Hashimoto's Thyroiditis - do not do the attacking. Your immune system attacks your thyroid, and the antibodies come along to clean up the blood after the attack.

During the attack, the dying cells leak their stores of thyroid hormone (plus some of the proteins TPO and Tg, hence the antibodies) into the blood. This causes the FT4 and FT3 levels to rise. And, because they rise, the TSH drops - the TSH doesn't do much independantly of the thyroid hormone levels.

So, all three levels can - and do - jump around.

The antibodies do not affect the thyroid hormone replacement you are taking in any way. Anymore than they affect the thyroid tissue. But, even when you are on a full replacement dose of thyroid hormone, the immune system continues to attack the thyroid, and will continue until the thyroid is completely dead. So, levels will continue to rise and fall as dying cells release their stock of hormone intermittantly.

The only way to know if your thyroid has been completely destroyed yet would be to stop your thyroid hormone replacement, wait six weeks and retest. I was told when I was 60 that my thyroid was completely dead, but when I was 68 - for reasons I won't go into here - I stopped my THR for six months. After six months, I noticed symptoms reappearing. I had a blood test and - surprise, surprise! - my thyroid wasn't dead at all. It had kept me alive for those six months, and whilst the TSH was high (45ish) the FT4/3 were just about in-range. So, it's possible that your thyroid still has the capacity to make hormone, if necessary, and still has some stores of hormone lef in remaining cells.

This is all theory, of course. I don't know anything about your thyroid. I'm just telling you how it works and what could possibly have happened to cause your high FT4.

[ak_83 in reply to greygoose]

Thanks greygoose , very informative. Maybe it is that.

[greygoose in reply to ak_83]

Could be.

[Buddy195 Administrator]

My FT4 level went over range a few months ago and I hadn’t changed my medication/ routine and was also perplexed. I cut back initially by 12.5mcg, then 25mcg and retested after 8 weeks on this reduced dose. My levels then went too low (for me) so I re-introduced 12.5mcg. Sometimes you only have to increase or decrease by a very small amount to find your ‘sweet spot’.

[ak_83 in reply to Buddy195]

Yes, I'm thinking the same. Rather than going from 150T4 down all the way to 100T4, I think I will just try 125T4. (25 mcg is the smallest increment that is locally available).

Thank you!

[Buddy195 Administrator in reply to ak_83]

I cut 25mcg in half using a pill cutter to make 12.5mcg (can buy cutters cheaply on Amazon if needed)

[tattybogle]

if this is first time you 've been on 150mcg levo for as long as 18 weeks , then yes, if dose is slightly to high, it will have built up. in which case probably only a small reduction is needed.

24.8[12-22] isn't much over range,, so i definitely wouldn't recommend anything as drastic as reducing to 100mcg , a 12.5mcg reduction might well be enough , 25mcg at the most.

But sometimes fT4 can just go up for no apparent reason , even when we have been stable on a dose for years... sometimes it might be because of an autoimmune attack causing thyroid to dump a load of ready made T4 into blood all at once , but sometimes, frankly, it's just a case of "we can't explain why , but it happened "

Mine went from 14.7 [7-14] 111% to 20 [7-14] 206% ....on same dose i'd been stable on for 3 years (and i still felt ok).... reduced dose by 12.5mcg , but weirdly it went UP even more to 22 [7-14] 242%.... lowered dose by another 12.5mcg... and it came down to 19 [7-14] 181%

But even more weirdly , despite it being 181% , i was now really undermedicated so GP reluctantly allowed me to increase by 12.5mcg ... and retested again in 6 months ... and despite INCREASE in dose ,fT4 had LOWERED to 16 [7-14] 140%

All tests done really carefully with correct timings .. i don't have any explanation.... might have been an autoimmune attack , but this was over a period of about a year and a half .... so i don't really know if i believe an autoimmune attack would be lasting that long .... so i have put it in the "??? don't know WTF that's about" box and moved on to see what will happen to it next.

[ak_83 in reply to tattybogle]

Wow, this is even more bizarre than my readings. I'll see how I go with 125T4 over the next 6-8 weeks. I do feel overstimulated - super tired and weigh 5 kgs less than my usual weight too now.

[tattybogle in reply to ak_83]

if you are feeling like that and have lost weight then i agree, 125mcg sounds like a good plan .