Strange test results - advice please

[Wired123]

Hi all,

I've got some strange results I am trying to understand. Been on a bit of a journey since starting T3 last November.

After taking T3 for the first 2 months Private Endo asked me to reduce T4 which didn't sit well with me and I had to increase it again.

I have been on the same dose of T3 10mcg for the entire time and now I'm on a regime of 6 days 150mcg Levo and 100mcg Levo on Sundays. So basically on 50mcg a week less than I was on before starting T3.

Prior to starting T3 I had been on 150mcg Levo for over 10 years.

My latest bloods show my T4 to be way down from historical levels and I don't quite understand why it's so low when the TSH is so close to zero and I'm only dropping my Levo by a tiny bit. Historically I have been in the 20-22 range for T4 on 150mcg a day.

How can a 5% a week drop in Levo drop my T4 by about half?

I'll also be posting private test results as soon as I receive them but these NHS results just don't seem to make sense to me.

All tests were fasting and 24 hours after Levo.

The Endo's protocol is to have the tests 5 hours after the T3 dose - so around 12.30pm for me.

He also feels the T4 level will be the same no matter what time it is taken.

I did the 9am test on the NHS to test this theory but it's thrown up more questions than answers!

[tattybogle]

Mmm ... curious.

remember that the % through the range is different for the wider[7.5-21.1] range

so the 11.2 fT4 result is 27 % through range , so it's not quite as low as it looks compared to the others , but still ... it's odd that it is so much lower than the previous 17.5 fT4 which is 55% through range. especially since the Levo dose is increased.

fT4 'ought' to be slightly less than the previous results on 150+ 10, so you'd expect something like 20 on the [7.5-21.1] range.

I 'm stumped.

Was the 11.2 fT4 much more than 24 hrs from last dose levo ?... clutching at straws

Sometimes i get fT4 results that just don't make sense, but usually they have gone up when they should have gone down , so i can theoretically blame whatever is left of my own thyroid for chucking out bit more T4.

But it's happened often enough to me that i no longer take too much notice of a single 'odd' result.

I'd see what next Endo results say before coming to any conclusions about the NHS 11.2

[Wired123 in reply to tattybogle]

I’m stumped too!

Levo was taken about 25 hours before so it can’t be that especially as it has a long half life.

I can understand the TSH jumping about due to Hashimoto’s but the T4 result is rather odd.

I’ll post my private results once I have them and see where they are at as this just does not make any sense.

I just looked back through my GP online service and historically (5 years of data) I have had results of 14-17.5 at the GP surgery which was all on 150mcg Levo only which has been my dose for over 10 years.

So it’s interesting that it does fluctuate a bit - I imagine due to activity, stress, diet, etc.

Still strange it’s gone that far lower now despite only a tiny drop in Levo.

I wonder if the NHS test is less sensitive however given the deviation from the private values as I shouldn’t be half way through the range on the NHS and near the top of the range privately as that’s how my historical results look.

[tattybogle in reply to Wired123]

So if NHS range has been the same [7.5-21.1]for a few yrs ? 14-17.5 is a 'usual' of roughly 50-70% through range for fT4 on 150mcg levo. And apparently adding T3 does sometimes reduce fT4 a little on same dose levo.

.....still clutching at straws !

Illogical results are much easier for Doctors to explain away , cos they can just blame us for 'not taking the tablets properly '... but when you know you have been, and have controlled the test conditions, it just makes you realise how complicated it all is, and how little they actually understand any of it.

Edit :

for example..

A while ago my fT4 on 125mcg was 14.7 [7.9-14] 111%.

Then a year later still on 125mcg ,it was 20.5 [7.9-14] 206%

So doc reduced to 112mcg .. and 2 months later

ft4 had gone up to 22.7 [7.9-14] 242%

.... Doctors assessment was that i'd 'misunderstood instructions' and taken more not less......

And then just to prove how daft it all is.... several months later when dose was increased ... my fT4 went down to 142%.... ??

Have since decided to take blood results with a large pinch of salt

[Wired123 in reply to tattybogle]

Wow that is erratic!

Could your change in dose also have changed activity in the actual thyroid gland through more stimulation via TSH changes?

[tattybogle in reply to Wired123]

No

TSH 0.046 = 111% fT4.....125mcg

0.041 = 206% ............125mcg

0.097 = 242%.............112mcg

0.51 =181%.............100mcg

Then later, an unusual 1.8 = 142%..... 112mcg

All totally illogical

[Wired123 in reply to tattybogle]

Mind blowing 🤯

[tattybogle in reply to Wired123]

I'm sure this is why the GP's are taught that the first 'suspect' for 'unexpected thyroid results' .. is US,,,, because if they actually had to explain it ... they wouldn't be able to.

[Bearo in reply to tattybogle]

I’m starting to think one of the reasons GPs love TSH results is that they are very reliable. FT4 and FT3, while more important, don’t seem to be very reliable blood tests.

[tattybogle in reply to Bearo]

More reliable in what sense ... accurate at measuring what's there in the blood ? I think technically TSH might win that one, but 'so what' if an accurate TSH count doesn't relate to what 's occurring with the hormones..... My personal experience is that both TSH and fT4 can be extremely misleading .. even if they are an 'accurate' measure.

eg. at start of treatment i had :-

DOSE.......TSH....fT4...... How i was feeling.

50mcg.....2.9......52%...... definitely 'not OK'

100mcg..2.5......68%.......improved but still 'not OK'

150mcg....2.7....71%.......pretty much 'OK'

If GP was going by TSH, which dose should i have been on ?

More recently i had:-

125mcg...0.046...111%

125mcg...0.041...206%

112mcg...0.097...242%

100mcg...0.511...181%

112mcg...1.947...142%

Which TSH is reliable to tell what state i'm in on a dose of 112mcg ? 0.097 , or 1.947

(all tests taken under same conditions)

I think TSH and fT4 both tell you 'not much at all' until you look at the whole picture of TSH /fT4/fT3 AND the History of results... and even then... quite often it makes no sense.

The wisest thing i read on here is thyroid replacement is more of an Art than a Science.

[Bearo in reply to tattybogle]

Agree totally. I just meant that the TSH assay seems reliable. You get the same number on any test. FT4 and probably FT3 seem to be harder to produce a result - more fragile, maybe, which is annoying when that’s what we need to know. No, TSH isn’t reliable at telling you very much, but it’s easy to test and produce a number.

Doubt I made that any clearer than the first time!

[tattybogle in reply to Bearo]

i get what you're saying.... all the different fT4 ranges really don't help matters either, Personally i refuse to believe the extremes of different ranges are really all that comparable , even if you do the % thing.

eg.

this example from when my lab changed from [8-18] to [7.9-14] which is both much narrower and much lower .

TSH......... fT4[range]...........% through range...... dose.............fT3...date ......GP

0.061.......13.9 [8-18]...................59%.....................125mcg......41%...2016....'OK'

0.046.......14.7 [7.9-14]............111%.....................125mcg......54%...2018....'OMG'

However these result are 2yrs apart. with some odd results in between.. so it's difficult to confront GP with the above as 'evidence' that the [7.9-14] test is crap , but diogenes thinks it is , so that's good enough for me..... he said it's too low , and too narrow and he wouldn't give house room to any diagnosis based on it.

I've also read that when you are right at the top /bottom of the fT4 tests it's harder for it to give a reliable result, but i got a bit lost in the science of 'why'.

[greygoose in reply to Wired123]

Having Hashi's can make all the levels fluctuate, not just the TSH.

[SlowDragon Administrator]

Your Ft4 is far too low. You need increase in levothyroxine

On almost any dose of T3 TSH is almost always suppressed and very unlikely to move even when inadequately treated

Aiming for Ft4 and Ft3 at least 60% through range

Always test as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

Day before test split T3 into 3 doses roughly 8 hours apart. 5mcg at 7am. 2.5mcg at 3pm and 2.5mcg at 9pm ...assuming testing 9am next morning

When were vitamin D, folate, ferritin and B12 last tested

What vitamin supplements are you currently taking

Presumably you have Hashimoto’s

Are you on strictly gluten free diet

[SlowDragon Administrator]

If you had to stay on current dose of 150mcg x 6 and 100 x 1 day week, you would be better to divide total per week into more equal doses per day

150 x 6 = 900 plus 100 = 1000mcg per week

Eg 137.5mcg x 4 days week and 150mcg x 3 days week = 1000mcg per week

[Wired123 in reply to SlowDragon]

Well the Endo’s advice was to just cut it on a Sunday just for ease of administration.

But what really doesn’t make sense is why a 50mcg cut a week leads to such a big drop in T4 levels.

Your first message says I need an increase in T4 but that would only just push me back to just outside the top end of the range of T4.

Will be an interesting chat with the Endo for sure as the TSH will be telling him to reduce dose whilst the T4 levels will tell him I’m “normal”.

[SlowDragon Administrator in reply to Wired123]

If he says you need to reduce dose because TSH is low ...you need a new endocrinologist

[Wired123 in reply to SlowDragon]

Believe it or not several Endos have said that to me before. This one is my ninth Endo, he’s the only one who thought I should go on T3 so I really don’t want to lose him.

I’ve seen all the “big” Harley Street professors, all been a big let down till this guy came along.

He’s a prat and I really dislike his attitude so would drop him in a heartbeat if I could find someone else but there’s a shortage of decent Thyroid doctors in London.

If anyone wants to recommend a good private Endo in London feel free to DM me, you are not allowed to name doctors on these pages for reasons I do not fully understand nor agree with as every other business can be reviewed online these days!

A private consultant is after all a business like a lawyer, accountant or architect and warrants no special treatment.