Thyroid UK
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Help interpreting thyroid blood test, please

Dear all

I posted on this forum a few days ago, about my chronic depression and tiredness, my suspicion of hypothyroidism, and my doctor's unwillingness to test my fT3 despite my TSH being above optimal and fT4 being at the low end of 'normal'. I paid Blue Horizons for further tests, and these are what I got (the TSH and fT4 agree with the NHS results):

CRP: 0.60 (<3.0 mg/L)

Ferritin: 56.0 (30 - 400 ug/L)

Free T4: 12.94 (12 - 22 pmol/L)

Free T3: 3.76 (3.1 - 6.8 pmol/L)

TSH: 2.69 (0.27 - 4.20 IU/L)

T4 Total: 80.0 (64.5 - 142.0 nmol/L)

Anti-Thyroidperoxidase abs: 7.4 (<34 kIU/L)

Anti-Thyroglobulin Abs: 17.8 (<115 kU/L)

Vitamin B12: 261 (Deficient <140 pmol/L; Insufficient 140 - 250; Consider reducing dose >725)

Serum Folate: 23.98 (10.4 - 42.4 nmol/L)

So I am at the low end of the range for fT3 as well, as I imagined I would be. But I don't know how to interpret B12, Ferritin and Folate, and I don't know what CRP is.

GIven my chronic depression and the fact that TSH, fT4 and fT3 are way off optimal, does anybody out there think a doctor (in Brighton?) will take my results seriously and consider thyroid medicine?

Kind regards.

9 Replies

The lab tests online site is very useful for basic information about many tests:


Magarlick, thyroid antibodies are negative for autoimmune thyroid disease (Hashimoto's). FT4 and FT3 are low in range but NHS is unlikely to diagnose hypothyroidism until TSH is over range, or FT4 below range. Some private doctors will make a diagnosis when TSH is >3.

B12 261 is low, PA Society recommend 1,000 is optimal. Supplement 5,000mcg methylcobalamin for 8-12 weeks then reduce to a maintenance dose of 1,000mcg. Take a B Complex to keep folate good and the other B vitamins balanced.

CRP is an inflammation marker so a low result is desirable.

Ferritin is low and this may be why you are tired. Supplement iron and take each tablet with 500mg-1,000mg vitamin C to aid absorption and minimise constipation.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


if Blue Horizons does an urinary iodine spot test, it may be a good idea. You guys in the UK can be living in low iodine areas and not be using iodized salt. Since antibodies are not contributory, possibly there's an iodine deficiency.

1 like

Gabkad, WHO designated UK and most of Europe iodine deficient in 2010.


Exactly. She should check if this is the only problem. Why end up on thyroxine and all the rest of this thyroid palaver when it may not be necessary?


Iodine available from

Worth a try.... If you have low thyroid levels but no antibodies it may be that your thyroid is just short of the raw materials to make hormones.

Xx g


IMHE you are hypothyroid and your ferritin and b12 are way too low

ferritin,folate,b12 and vitd3 need to all be halfway in their ranges

most gps will not treat you unless your tsh is over 5 or even 10

so you may need to consider self medicating but the possibility of low iodine should be explored first


Thanks for all of your replies.


Hello Magarlick

My daughter's results and symptoms are similar to yours. On the advice of list mates we asked the GP to test her cortisol (which is needed for cells to take up thyroid hormone). Her cortisol test came out very low and she is waiting for Endo appointment and further tests to establish the cause of adrenal problems. The cortisol blood test must be done at 9am. Apparently saliva tests give much more information than blood tests, I'm sure other list mates will advise you about cortisol saliva tests.


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