I have since been put on Levothyroxine 50mg which brought my Serum TSH level down to 1.54mIU/L.
The GP told me that it would very likely be autoimmune, and wasn’t very keen on checking this until I pushed for it. The results that came back are:
Thyroid autoantibodies: 16 IU/ml (normal range -100) All satisfactory.
Do these results mean that my hypothyroidism is not autoimmune? And if so, what other causes could there be?
I wondered if it could be lack of iodine due to a previous vegan diet at time of diagnosis. I have since started eating dairy.
Is hypothyroidism due to lack of iodine reversible or do people still need to take lifelong medication?
Should I be asking the doctor to check something else?
Thank you for helping- I feel a bit bewildered and don’t understand what next steps I should be taking.
P.s I’ve read on here that blood should only be taken right at the beginning of the day, 24hours since last dose of levothyroxine, and on an empty stomach. I haven’t been asked to do any of this by my gp and have just had to go when the doctor had an appointment available and could fit me in! Does that render these results invalid?
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50mcg levothyroxine is only a starter dose. Typically dose is increased slowly upwards in 25mcg steps over several months until TSH around one, Ft4 and Ft3 at least 50% through range
Which brand of levothyroxine are you currently taking
Bloods should be retested 6-8 weeks after each dose change or brand change in levothyroxine
For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.
NHS won’t test TG antibodies unless TPO are high
Significant minority of Hashimoto’s patients only have high TG thyroid antibodies
Very important to test vitamin D, folate, ferritin and B12 at least once year minimum
If been vegetarian or vegan low B12 and/or low iron/ferritin highly likely
Low vitamin levels are extremely common, especially with autoimmune thyroid disease (Hashimoto’s or Ord’s thyroiditis)
Autoimmune thyroid disease with goitre is Hashimoto’s
Autoimmune thyroid disease without goitre is Ord’s thyroiditis. Both are autoimmune and generally called Hashimoto’s.
In U.K. medics hardly ever refer to autoimmune thyroid disease as Hashimoto’s (or Ord’s thyroiditis)
Recommended on here that all thyroid blood tests early morning, ideally before 9am last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins
List of private testing options and money off codes
This is such a helpful response, thank you- you’ve given plenty of info I wouldn’t have thought about checking. I will definitely look into testing the things you’ve suggested. Thank you for the advice and links!
Click on "Read the list of available tests" and on page 3 of the pdf you'll see
Urine Iodine Test:
Specimen requirements: Urine
Cost: £71.00
Order Code: END25
Turnaround time: 5 - 10 days
Iodine is an essential trace element, vital for healthy thyroid function. Adequate levels are required to enable the production of T3 and T4 thyroid hormones, whilst also being required in other areas of health.
Deficiencies can lead to impaired heat and energy production, mental function and slow metabolism. Urine iodine is one of the best measures of iodine status. This test is not performed as a loading test, but can be used to establish existing levels or to monitor iodine supplementation.
Autoimmune thyroid disease (Hashimoto's) is the most common cause of hypothyroidism. Your low antibody result discounts Hashi's with that test. However, antibodies fluctuate and it's possible that future tests could show a higher level, lower level, same level or over range result. It's also possible to have Hashi's without positive antibodies.
However, there are many other causes of hypothyroidism. Mine is non-autoimmune and it just happened when I was in my mid-20s, I'd had a baby a few months previously but too long had passed for me to think that was definitely the cause but I honestly don't know. My mother developed hypothyroidism in her 60s. My sister-in-law developed it too in her 40s. We all lived in Birmingham and that was the first area to have flouride added to drinking water in the 1960s and that is said to be a cause.
Other causes (taken from Dr Peatfield's book "Your thyroid and how to keep it healthy"):
Genetic - thyroid gland may not develop properly in the womb, may be totally inactive or partially inactive.
Environment - iodine deficiency, selenium deficiency, environmental poisons such as mercury, fluoride (not naturally occurring fluoride but the toxic waste fluoride added to toothpastes, water, etc).
Thanks so much for your response, it’s really helpful to hear about people’s personal experiences on here, and it’s really interesting to read about the possible causes. You’ve given me plenty to look into, thank you
I have non autoimmune hypothyroid, at least my antibodies have never been raised on the two occasions I've had them tested. Sometimes the thyroid just fails. I'm a lifelong vegetarian, maybe my diet contributed.
I've personally got a feeling my pituitary gland got damaged in childbirth as I lost a lot of blood very suddenly and this can damage the pituitary. As a result the thyroid can be impacted as the pituitary is the master gland which also controls the thyroid. Who knows? The treatment is the same whether it's autoimmune or not.
I don't know if hypothyroidism which is not autoimmune is reversible. Once it starts failing it normally requires us to take levothyroxine to keep us healthy. There are temporary conditions which cause the thyroid to play up, sometimes a virus or having a baby can cause blips.
Your results are probably not strictly accurate. Your TSH would probably be higher in the morning before eating or drinking. If you took your Levo not long before the blood test then your FT4 will be artificially high. How do you feel on your results? That's the crucial question.
Thank you for your insights into this. I’m certainly learning from this forum and from everyone’s responses that the cause of this condition can be incredibly varied. I still have some symptoms that aren’t improving, so I think you’re right- further testing needed, and under more controlled conditions. Thank you for your advice!
50mcg levothyroxine is only the standard starter dose levothyroxine
You will need further increase in levothyroxine over coming months
guidelines on dose levothyroxine by weight
Even if we frequently don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose
Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.
Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.
For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.
For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).
If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.
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