I have been on and off out of sorts for awhile now. I had blood tests done in July including for my thyroid, all within range. I looked at the results last night again for no real reason and noticed that my free T4 by many lab reference ranges is low.
My result was:
TSH 1.41 mu/L
Free T4 (thyroxine): 10.86 pmol/L
The reference ranges given are 0.35 - 3.5 for TSH, and 7.5 - 21.1 for thyroxine. However digging around online I find many trusts have a range of 12 - 22 or 10 - 20. Some have a range from 7 or 8 but this seems less common. I've read different labs have different reference ranges, is this because the test itself is different or is it just each labs discretion? I guess I mean would I have got the same result if the test had been done in an NHS trust with a reference range of 12-22 or is the test itself different? I guess in my head 10.86 pmol/L is just the amount in my blood regardless of lab reference ranges?
I read a bit more and it seems normal TSH and low T4 can be indicative of secondary hypothyroidism. I look up symptoms and so many match me - sensitive to cold, headaches, tiredness, muscle and joint pain, low mood, hair loss etc. I don't have particularly dry skin or hair but otherwise so much is similar. I also have further risk factors by being female and a family history of pituitary disorders, my mother had some growth problem as a child with lots of time off school with painfully fast growth, early puberty etc.
I also have sore neck glands down into my collar bones and last time she saw me she said 'ooh I think you're unwell, you're very lumpy bumpy' but then when bloods were 'within range' that was it.
I have had thyroid tests before and TSH have always been similar.
July 2021 (as above):
TSH 1.41
T4 10.86
April 2021:
TSH 1.2
T4 11.5
August 2013:
TSH 1.84
T4 12
July 2009:
TSH 1. 2
T4 12
I'm 32 with two children. Any thoughts or advice if what to do next hugely appreciated.
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Goldenbeetle
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This is on the low side. Ferritin is recommended to be half way through range although some experts say that the optimal level for thyoid function is 90-110ug/L.
You can help raise your level by eating liver regularly, maximum 200g per week due to it's high Vit A content, also liver pate, black pudding, and including lots of iron rich foods in your diet
Don't consider taking an iron supplement unless you do an iron panel, if you already have a decent level of serum iron and a good saturation percentage then taking iron tablets can push your iron level even higher, too much iron is as bad as too little.
Serum vitamin B12 level 509 ng/L [187.0 - 883.0] (ng/L is the same as pg/ml)
This could be higher but it's not B12 deficiency.
According to an extract from the book, "Could it be B12?" by Sally M. Pacholok:
"We believe that the 'normal' serum B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebrospinal fluid below 550".
"For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1000 pg/ml."
Serum folate level 6.3 ug/L [2.7 - 15.0]
Folate is recommended to be at least half way through range, so that would be 9+ with that range.
To improve both B12 and folate levels you could supplement with a good quality B Complex. My preference is Thorne Basic B. If you look at different brands then look for the words "bioavailable" or "bioactive" and ensure they contain methylcobalamin (not cyanocobalamin) and methylfolate (not folic acid). Avoid any that contain Vit C as this stops the body from using the B12. Vit C and B12 need to be taken 2 hours apart.
When taking a B Complex we should leave this off for 3-7 days before any blood test because it contains biotin and this gives false results when biotin is used in the testing procedure (which most labs do).
Did you have Vit D tested? That would complete the key nutrient tests.
Reference ranges vary from lab to lab, this is because machines are calibrated differently and also local population is taken into account. So it doesn't matter what any other range is, the only range appropriate to your result is the one your lab uses. If you had your blood tested at a different lab with a different range on the same day it wouldn't be the same result, it would in fact be the same percentage through range. So if your FT4 is 10.86 with a range of 7.5 - 21.1 then that is 24.71% through range. If the other lab's range is 12-22 then your result would come out as 14.47.
For secondary hypothyroidism your FT4 would have to be at the very bottom or below range.
Symptoms of secondary hypothyroidism will be the same as any other form of hypothyroidism - Primary, Autoimmune, Non-Autoimmune.
Thank you very much for clarifying the reference ranges. Perhaps thyroid is not the issue for me! Your info about ferritin is useful too. I think my diet could do with a bit of an overhaul anyway.
I've previously been low in vitamin D, in 2014 it was 19 nmol/L with a range of 50 - 120. In 2019, it was up to 52nmol/L, same range. I supplement as often as I remember with 5000iu Thorne D3 now though. I've requested another vit D test today to check though.
I've previously been low in vitamin D, in 2014 it was 19 nmol/L with a range of 50 - 120. In 2019, it was up to 52nmol/L, same range.
So at 19nmol/L that was Vit D deficiency. Did your GP treat this according to NICE guidelines with loading doses? You should have been given 300,000iu D3 over a period of about 6 or 7 weeks and then this should have been followed with a reduced dose according to new test result.
To only achieve 52nmol/L in 5 years is nothing short of neglect if your GP knew about your deficiency.
I was severely deficient with a level of 15nmol/L but I discovered this myself and self supplemented, never involved my GP. I raised my level to 202 in 2.5 months and have since maintained it at 150nmol/L since then.
When you take your D3 do you also take it's important cofactors - magnesium and Vit K2-MK7?
D3 aids absorption of calcium from food and Vit K2-MK7 directs the calcium to bones and teeth where it is needed and away from arteries and soft tissues where it can be deposited and cause problems such as hardening of the arteries, kidney stones, etc. 90-100mcg K2-MK7 is enough for up to 10,000iu D3.
D3 and K2 are fat soluble so should be taken with the fattiest meal of the day, D3 four hours away from thyroid meds if taking D3 as tablets/capsules/softgels, no necessity if using an oral spray.
I've just looked at Thorne 5,000iu and it seems to be around £20 or more for 60 capsules and besides D3 it contains microcrystalline cellulose, hypromellose capsule, leucine, silicon dioxide, vitamin E (d-alpha tocopheryl)
For D3 I like, and have always used, Doctor's Best D3 softgels, they are an oil based very small softgel which contains just two ingredients - D3 and extra virgin olive oil, a good quality, nice clean supplement which is budget friendly. I pay £16.99 for 360 x 5,000iu capsules.
For Vit K2-MK7 I like Vitabay or Vegavero brands which contain the correct form of K2-MK7 - the "All Trans" form rather than the "Cis" form. The All Trans form is the bioactive form, a bit like methylfolate is the bioactive form of folic acid.
Magnesium helps D3 to work. We need magnesium so that the body utilises D3, it's required to convert Vit D into it's active form, and large doses of D3 can induce depletion of magnesium. So it's important we ensure we take magnesium when supplementing with D3.
Magnesium comes in different forms, check to see which would suit you best and as it's calming it's best taken in the evening, four hours away from thyroid meds if taking magnesium as tablets/capsules, no necessity if using topical forms of magnesium.
If you come back with your new Vit D result I'll work out what dose you will need to achieve the level recommended by the Vit D Society and Grassroots Health, which is 100-150nmol/L with a recent blog post on Grassroots Health recommending at least 125nmol/L.
The GP did briefly prescribe some higher dose vitamin D but there was no follow up and they were very happy I was in range at 52(!) so then it was left. Thanks for the D3 recommendation, I've been wanting to switch to a different brand that's cheaper/easier to get but didn't know where to start. I do take the D with the fattiest meal but haven't been supplementing with magnesium except briefly awhile back or K2. The only other supplements I have are Zinc and Vit C. I'll have a look at those links and get some ordered.GP are ringing today so hopefully will be happy to test my levels otherwise I'll order my own test.
Thanks again for the advice. It's so helpful and I really appreciate it.
there was no follow up and they were very happy I was in range at 52(!) so then it was left.
This is a big problem. Doctors aren't taught anything about nutrition so they are only obliged to get you out of deficiency and into "sufficient" range which is >50. It's still far too low. They also think that everyone can make Vit D naturally from the sun in the summer and that's not so, not everyone does.
I'll have a look at those links and get some ordered.GP are ringing today so hopefully will be happy to test my levels otherwise I'll order my own test.
Don't order any D3 until you know your current level. It's essential to dose at the right level, post your new result and I'll work out what you will need.
Suggest you work on getting all four vitamins optimal
Then get FULL thyroid and vitamin testing done in 2-3 months
ALWAYS test thyroid levels as early as possible in morning before eating or drinking anything other than water
For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.
Very important to test vitamin D, folate, ferritin and B12
Low vitamin levels are extremely common, especially with autoimmune thyroid disease (Hashimoto’s or Ord’s thyroiditis)
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
If in U.K.
Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins
If TPO or TG thyroid antibodies are high this is usually due to Hashimoto’s (commonly known in UK as autoimmune thyroid disease). Ord’s is autoimmune without goitre.
About 90% of all primary hypothyroidism in Uk is due to Hashimoto’s. Low vitamin levels are particularly common with Hashimoto’s. Gluten intolerance is often a hidden issue too
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