I have subclinical hypothyroidism and have been on 50mcg of levothyroxine for a while (a year?), after my TSH level went over 10mIU/L.
I moved to Bristol recently, and had a blood test as I was experiencing fatigue, weight gain, and many other symptoms of hypothyroidism. I was told my blood test was abnormal.
Despite my TSH previously being around 2.5mIU/L, it's now raised to 6.88mIU/L.
However, my GP said my T4 is way too high at 14.4pmol/L, and he said I shouldn't have an increase in levothyroxine. I was really surprised, as previously my T4 has been in range when it's been much higher, at around 20-21pmol/L.
However, I saw that NHS Bristol have changed their T4 reference range, which is now: 7.9 – 14.4 pmol/L!
I feel really awful and I'm not sure what to do, as now my T4 is too high and off the charts at 14.4pmol/L!
My GP was really dismissive anyway, but I'm so shocked at how the NHS Bristol ranges for T4 are significantly lower than the ranges used in other parts of the UK, which is usually around 10 - 24 pmol/L.
I also don't know why my T4 and TSH are high.
Is there anything to be done to get NHS Bristol to change their bizarrely low T4 ranges?!
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melissa-b
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hi, sorry for replying late! It was early morning and I took that day’s dose of levothyroxine after the blood was taken. I’m currently not on any vitamins but I was taking vitamin D until about January as I was also deficient in Oct/Nov! I’ll ask to see another GP, thank you ♥️
With serum B12 result below 500, (Or active B12 below 70) recommended to be taking a separate B12 supplement and add a separate vitamin B Complex after a week
Then once your serum B12 is over 500 (or Active B12 level has reached 70), you may be able to reduce then stop the B12 and just carry on with the B Complex.
If Vegetarian or vegan likely to need ongoing separate B12 few times a week
IMPORTANT......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 7 days before ALL BLOOD TESTS , as biotin can falsely affect test results
In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate methyl folate supplement and continue separate B12
How other member saw how effective improving low B vitamins has been
Melissa ranges are not set at random and cannot be chosen. The testing labs set the ranges based on the testing equipment and procedure they use. A change of range means that NHS Bristol has either changed the lab they use or the lab has upgraded it's equipment.
in theory, if you sent the same blood sample to a lab that used a 10-24 range , the fT4 result would still come back as top end of the range eg 24 ish.
The only way to prove if this is true in practice is to send 2 samples (both taken at same blood draw) to 2 diff labs and compare both results.
you could try querying this fT4 result with GP and ask them to arrange this , but the chances of them agreeing to do it are slim ( the fact that TSH is so high at the same time as a high fT4 result is unusual and might trigger a GP's interest)
(Note ~ how long before the test did you take the last dose of Levo ? .this timing does affect fT4 result .. fT4 tests taken within approx 6 hrs from last dose will be higher than when tested 12-24 hrs after dose as there is a peak in fT4 blood levels lasting for a few hrs after the dose is taken ~ usually 2-4 hrs after taking the tablet is the highest level , but the exact timing depends on how fast your digestive system absorbed the tablet)
I'm so shocked at how the NHS Bristol ranges for T4 are significantly lower than the ranges used in other parts of the UK, which is usually around 10 - 24 pmol/L.
They vary a lot throughout the UK, my NHS range is 7-17, it changed from 11.8-24.6 some time between 2014 to 2017.
Your results are unusual in that you have a top of the range FT4 with an over range TSH. If GP wont retest then you might want to consider doing a private test. If you use Montor My Health they are an NHS lab at Exeter hospital so the results should be acceptable to your GP, otherwise you could use Medichecks or Blue Horizon but remember to do all your thyroid tests as we suggest:
* Book the first appointment of the morning, or with private tests at home no later than 9am. This is because TSH is highest early morning and lowers throughout the day.
In fact, 9am is the perfect time, see first graph here, it shows TSH is highest around midnight - 4am (when we can't get a blood draw), then lowers, next high is at 9am then lowers before it starts it's climb again about 9pm:
If we are looking for a diagnosis of hypothyroidism, or looking for an increase in dose or to avoid a reduction then we need TSH to be as high as possible.
* Nothing to eat or drink except water before the test - have your evening meal/supper as normal the night before but delay breakfast on the day of the test and drink water only until after the blood draw. Certain foods may lower TSH, caffeine containing drinks affect TSH.
* If taking thyroid hormone replacement, last dose of Levo should be 24 hours before blood draw. If taking NDT or T3 then last dose should be 8-12 hours before blood draw, split dose and adjust timing the day before if necessary. This avoids measuring hormone levels at their peak after ingestion of hormone replacement. Take your thyroid meds after the blood draw. Taking your dose too close to the blood draw will give false high results, leaving any longer gap will give false low results.
* If you take Biotin or a B Complex containing Biotin (B7), leave this off for 3-7 days before any blood test. This is because if Biotin is used in the testing procedure it can give false results (most labs use biotin).
These are patient to patient tips which we don't discuss with phlebotomists or doctors.
Unfortunately, you have encountered a uniquely grim situation in FT4 testing. The correct healthy range is around 11-23. The new test I am certain is the Abbott test, which has an absurdly low range spread. In one sense it doesn't matter in that you can proportionalise the values from the first and from the Abbott test. So for example the ratio of old test/new one at the low reference point is 11/7.9 or 1.39/1, and for the high reference number 23/14.4 or 1.6/1. So, if you are about midrange I'd say theconversion factor is about 1.50/1 old test/Abbott. This refusal to rationalise FT4 tests from various manufacturers is one of the worst scandals of present day thyroid treatment.
Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization
Critical Reviews in Clinical Laboratory Sciences| Received 28 Mar 2022, Accepted 03 Sep 2022, Published online: 13 Oct 2022 doi.org/10.1080/10408363.20...
thank you so much - it seemed so bizarre! Makes sense if it’s proportionate, but then my high tsh and high t4 would still not make any sense… hopefully a second opinion will get me some answers!
That happened to me and was teated for free t3 along with t4 t3 was very low so now on combination t4 and compounded t3 med. Finally went to naturopath. Has helped alot
Some of you may be interested in Dr Myhill talking about the thyroid. If you go on her website and in the search bar type thyroid.She has a page on persuading the GP to do a thyroid test, how the UK TSH range should be changed, and other information such as some people need to run at the higher normal range.
You may be told by your GP your TSH is within range so they won't test the T3 or T4. But don't listen to the symptoms you experience. She talks about this.
There is more than one page, so make sure to read all pages by searching "thyroid".
She can do the tests and let you know her opinion, which is charged for. She can suggest what dosages, and I suggest this reading because she seems to look beyond what a GP is willing to do. If anything you may be interested in the reading and find out more, it's free information.
"Poor conversion of T4 to T3 – where the most active thyroid hormone, i.e. T3, is low. TSH may be high and the free T4 may be high.
In deciding whether to treat, one must consider both the symptoms and the blood tests. Many doctors just treat the blood levels. The issue here is that one's personal normal range of thyroid hormones is not the same as the population normal range. Some people feel much better running high normal rather than low normal levels of T4 and T3.
The third type of under-functioning is due to poor conversion of T4 to T3. This requires enzymes and co-factors, in particular selenium, zinc and iron."
This is what I read on Dr myhills website under thyroid. If you go to the search bar and type thyroid you can see more than one page to read on thyroid.
I think you may get something out of this information.
She can do tests and explain ranges to you to, and what medication to give.
But the information is free to read.
I would recommend seeing it this helps.
On another website I read " Skinner thought many people can't convert T4 into active hormone T3"
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Dose adjustment - thyroxine. 
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Iron and Thyroid results 
Reference ranges
