Thyroid UK
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Blood test results - help please!

Is anyone able to help me understand my blood test?

TSH 0.87mIU/L

FT4 19.3 pmol/l

T3 1.3 nmol/L

Vit D 71 nmol/L

Iron 9.4 umol/L

Transferrrin saturation 18%

Ferritin 138 ug/L

I've been showing signs of hypothyroidism - fatigue, swollen joints, CTS. I take 125 mcg levothyroxine. If I'm not converting T4 to T3, how can this be improved?

I look forward to any informed feedback.

Best wishes,


5 Replies

Have you got any ranges for those figures Toby? They vary quite a bit depending on the lab that runs the tests.



TSH 0.87mIU/L 0.27-4.2

FT4 19.3 pmol/l 12.0-22.0

T3 1.3 nmol/L 1.3-3.1

Vit D 71 nmol/L 50-200

Iron 9.4 umol/L 10.6-28.3

Transferrrin saturation 18% 20-55

Ferritin 138 ug/L 30-400




vit d all way too low hence inability to convert t4 into t3 your cells are screaming for

cholesterol is likely high and LFTs could be strange

probable central /2ndary hypothyroid due to pituarity failure is indicated by LOW TSH


would the tsh not be that low due to the amount of levothyroxine being taken? just trying to get my head round how all these things work together :-)


Toby's TSH isn't low, his FT3 is. As his FT4 is good, being in the top 75% of range, this indicates he isn't converting T4>T3 in his liver.

His low iron and ferritin are almost certainly preventing proper absorption and conversion.

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