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Thyroid UK
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Confused by recent test - TSH and antibodies down, but also a drop in FT4 and FT3?

I’ve been a member of this forum for a few months now and it’s been such a great help - I now understand my thyroid so much better and have taken getting well into my own hands (as predictably, my GP is clueless).

I was diagnosed with Hashimotos almost 2 years ago. I did a thyroid/vitamin test 2 months ago, on 26 Oct (results below - it was an improvement on a test done some months previously), and since then have gone strictly gluten free. I’ve also been supplementing for the last 5 months (which I believe resulted in improvement to my blood work in Oct).

I’ve just done another blood test (didn’t meant to so soon, but an opportunity came up) and I’m confused by the results. There seems to be progress again (lower TSH and lower anti TPO) but I’m also now in the lower normal range for FT4 and FT3.

I thought if TSH and antibodies improved, so would FT4 and FT3? It seems like a big drop as well.

What do you all think?


27 Dec

TSH 2.13 (0.27-4.2)

FT3 3.2 (3.1-6.8)

FT4 14.5 (12-22)

ATG not taken

AntiTPO 118.8 (0-34)

Ferritin 126 (13-150)

CRP 0.6 (0-5)

Vitamins not taken

26 Oct

TSH 4.19 (0.27-4.2)

FT3 5.77 (3.1-6.8)

FT4 16.2 (12-22)

ATG 27.8 (0-115)

AntiTPO 161 (0-34)

Ferritin 164 (13-150)

ACTIVE Vit B12 177 (25.10-165) - reduced supplement dose now

Folate 19.98 (2.91-50)

Vit D (25OH) 123 (50-200) - taking maintenance dose now

CRP 1.4 (0-5)

20 July

TSH 5.48 (0.27-4.2)

FT3 5.9 (3.1-6.8)

FT4 14.8 (12-22)

ATG 64.0 (0-115)

AntiTPO 204.9 (0-34)

Also Vit B12 629 (211-911)

CRP 1.1 (0.1-5)

All tests taken first thing around 9am on an empty stomach.

I don’t take any medication. I still feel the same, i.e. mostly asymptomatic (only suffer from cold hands and feet and my digestion is not always the best).

I’d love to get your opinion on whether this is an improvement still, or if lower FT3 and FT4 suggest it’s not, or if it’s all more complicated than that! Thanks everyone.

7 Replies


The higher TSH will stimulate the thyroid gland to produce more T4 and T3. When TSH stimulation drops so might T4 and T3 levels. Thyroid levels will be higher after an autoimmune attack on your thyroid and will subside in between attacks but don't affect TSH, T4 and T3 levels.

NHS won't usually diagnose hypothyroidism until TSH is over range or FT4 below range. Supplementing 100-200mcg selenium may support thyroid and delay progression to hypothyroidism.

Thyroid peroxidase antibodies are positive for autoimmune thyroid disease (Hashimoto's). There is no cure for Hashimoto's which causes 90% of hypothyroidism. Levothyroxine treatment is for the low thyroid levels it causes. Many people have found that 100% gluten-free diet is helpful in reducing Hashi flares, symptoms and eventually antibodies.



Ferritin was over range in October indicating inflammation or infection in the body but has dropped into range in December.

CRP is also lower in Dec which indicates inflammation is reduced.

B12, folate and vitD were good in October.


Thanks that’s helpful! I already supplement, including with selenium - I think it’s really helped as previous to that both my TSH and antibodies were higher with each test. I’ve also been GF for the last two months, but don’t notice much difference symptom wise. All the best.



Most people will need at least 6 months gluten free before noticing improvement in symptoms as it takes that long for the gut villii to repair. In terms of reducing antibodies it can take 2-3 years g-f.

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There is no direct connection between your antibody levels and FT4/3 levels. Antibodies fluctuate all the time, independant of the Frees and the TSH. And, a dip in antibody levels doesn't mean your Frees are going to improve. Two separate problems.


Thanks Greygoose, that’s really helpful to understand - despite all my reading don’t think I had! Ignoring the antibodies, I’m still confused about how to read the results though - does this indicate worse or better thyroid function than before, since my last test? Is some kind of improvement, or is it difficult to say? Thanks! :-)

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How you feel is the best indicator of better and worse thyroid function. Usually increasing FT4 and FT3 levels with dropping TSH level indicates improvement.

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Thanks, appreciate the reply! And yes, I’ll definitely stick to GF diet for at least 6 months - it’s making me eat healthier overall as I’m cooking meals at home more (rather than relying on quick sandwich or ready meal).



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