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Thyroid UK
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Help with results please

Had an increase in Thyroxine about 8 weeks ago (125 to 150).

Had bloods done and would appreciate help with results.

Vit D 43

TSH 0.1 = 0.27-4.20ml/U/L

free T4 23.47 = 12.00-22.00pmol/L

Serum folate 8.4 = 2.50-19.50ug/L

Serum ferritin 33 = 30.00-470.00ug/L

Vitamin B12 400 = 180.00-900.00ng/L

Free T3 3.9 = 3.10-6.80pmol/L

CRP 5 = <6.00mg/L

Have to make telephone appointment with doctor to discuss TSH and FT4 levels.

Am worried that she will request I reduce thyroxine which I dont really want to do as since increasing dose I have felt much better in myself and have finally started slowly losing the 3/4 stone I have put on over the last couple of years.

Opinions please.

13 Replies

Did you skip your dose the day before and morning of your test?


No never have but do take them very early in the morning (6.30am).


If you took thyroid hormones on the morning of the test, your results will be skewed. So ask the doctor to have another and you should allow 24 hours between your last dose of hormone and the test and take them afterwards. The blood test should also be the very earliest possible, fasting (you can drink water).

1 like

Personally, If I'm planning on going to give a blood sample, I skip my T3/T4 both the day before and the morning of the test and take them with me to take afterwards. I find I get a more accurate picture of my levels rather than a system I've just flooded with hormone a couple of hours previously.

I'm not a healthcare professional and I'm not suggesting you do this, just sharing my experience.



You won't get an accurate picture of your FT3 if you leave more than 8-12 hours between last dose and blood draw and you don't need to skip the Levothyroxine dose the day before testing.


Hi Clutter

Thanks for the information. So should I take both my Levo and T3 before my blood draw as normal? Generally I take my medication in the morning and would have the blood draw around an hour later. I read that it can give an inaccurate higher result so I would appreciate your thoughts.



The T4 and T3 can peak in your blood for up to 8 hours which can give high FT4 and FT3 results so you should take them after your blood draw.


That's great, thank you for your help.


Tell her as your your FT4 is above range and your FT3 is at the bottom of the range you are still not on sufficient hormones, regardless of what the TSH say. They have been told that low TSH means danger of heart attacks, which hasn't been proven I'm sure unless the patient already had a heart disease.

I think, and am not medically qualified that you aren't converting T4 to sufficient T3. T4, levothyroxine, is inactive and its job is to convert to t3. Both FT4 and FT3 should be towards the top of the range. FT4 is over and FT3 below.

If she's concerned about low TSH - she should be more concerned about your low FT3 and I'll give you a link and you can discuss with her.


An excerpt from the above:-


T4 converts to T3 and is the only thyroid hormone actually used by the body's cells.

The approx. reference range for Free T3 is 4 to 8.3

We at Thyroid UK believe that you need to know your Free T3 level too because this will often show low if you are not converting, and high if you have blocked receptor cells. Even if you are converting, the body needs the extra T3 that a normal thyroid produces. There has been some research to show that people feel better on a mixture of Thyroxine (T4) and Triiodothyronine (T3). Effects of Thyroxine as Compared with Thyroxine plus Triiodothyronine in patients with hypothyroidism – The New England Journal of Medicine Feb.11, 99 Vol. 340. (Click here for this article).


Any advise on other levels please.


I am not brilliant at bloods in general and I see that puncturedbicycle has responded.

To raise your B12 you should supplement with methylcobalamin sublingual B12. Usually our stomachs aren't so good so sublingual is best.


Your folate, ferritin and b12 are low. This may be why your levo is sort of backing up (t4 is high and t3 low), it isn't converting as well as it might. This can also be caused by taking your meds to close to the blood draw but you know now, next time you'll take it afterward. Any idea if your d is ok? Most of us are in need of that too.

When you speak to your doc you may want to say oops, I took my meds in the morning (doc will say it makes no difference :-) ) and, as it was thought to be necessary to raise my meds last time, rather than yoyo back down I'd like to stay on this level for another six weeks and test again. See if that works. Point out that you have to symptoms of overmedication (if you have none). If you don't get anywhere you can be more emphatic and say you refuse a dose reduction. Good luck.



Levothyroxine can peak in your blood for up to 8 hours so you should take it after your blood draw. You could tell your GP that is why FT4 is over range. Some patients need FT4 over range to feel well and that will suppress TSH. Your FT3 is low in range. Read Treatment Options in thyroiduk.org.uk/tuk/about_... Email louise.roberts@thyroiduk.org.uk if you would like a copy of the Pulse article to show your GP.

VitD 43 is sub optimal. VitD is replete 75-200 and most people are comfortable around 100. I would supplement 5,000iu D3 for 8 weeks then reduce to 5,000iu alternate days and retest in July/August. Take vitamin D 4 hours away from Levothyroxine.

Ferritin is optimal halfway through range. You can raise ferritin by supplementing iron with 1,000mcg vitamin C which aids absorption and minimises constipation. Take iron 4 hours away from Levothyroxine.

Folate and B12 levels look okay.


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