Thyroid UK
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Hi Everyone just to say that my very helpful receptionist at our Doctors has kindly run off the reading of my throid tests BUT in a nutshell I am confused about how to read them.

June 06 Plasma TSH 0.1,Plasma free T4 19.09

Sept 06 Serum Free T4 18.22

Serum TSH 0.02 TSH 0.02

June 07 Serum Free T4 16.8

Serum TSH 0.04

Dec 07 Serum Free T4 18.63

Serum TSH 1.23 TSH 1.23

Dec 08 Serum Free T4 13.32

Serum TSH 40.18 TSH 40.18

Apr 09 Serum Free T4 20.68

Serum TSH 0.1

Feb 10 Serum Free T4 21.04

Serum TSH 0.06

Are they ok? I was told in Feb I needed to reduce my Thyroxine from 125mcg to 100mcg but strange things are happening.....Eagerley awaiting any responses!!!

6 Replies

Sunshine, with blood test results you always need to know the lab ranges i.e. in my area the Free T4 lab range is 12 to 22 but in other areas it could be lower.

If you cannot see the lab ranges on your printed sheet then the receptionist can find out for you, just ask her for the lab ranges for TSH and Free T4.

Your last results were very much the same as mine and I was not told to reduce my meds. Some doctors are not happy if your TSH is supressed, but if you have symptoms returning then you are better on the 125mcg ... IN MY OPINION. I am not a medical expert.

The little book that you can buy from good pharmacists around £5 on thyroid will help your case not to reduce your dose because Dr Toft mentions that often some patients are not well until their TSH is under 1 and their Free T4 at or above the lab range.

Try and keep notes of how you feel on the different doses, ask your GP as nicely as possible if he/she could treat your symptoms rather than your blood test results.

Good luck


Thank you Suze for your time and 'non professional' advice. I will keep a diary and I will have a look for that book you have mentioned.


It is worth getting to show your GP where Dr Toft says it is sometimes need for TSH to be suppressed and ft4 at the top or even above the range. However, I would recommend other books for a more understanding view of thyroid disease. Keep us posted.


Thank You Suze, will do


Hi Sunshine,

I agree that you need to get your reference ranges as this will give us a better picture and more to work on. I must stress that none of us are medically qualified here but we can give you the benefit of our experience to enable you to talk to your doctor about this.

Your results are all over the place – your TSH is extremely high at 40.18 in Dec. 08! Did you have your medication reduced prior to that by any chance? I see in another post that you had your meds reduced earlier this year and have had some hair loss – was this since the reduction? If so it would be a good idea to try to get another thyroid test done and see what your levels are like now. If you keep a note of how much thyroxine you are on at the time of each test and also how you feel you will be able to chart your progress (or otherwise!) more easily.

I find the best time to have my test done is first thing in the morning and before I take my thyroid meds. TSH levels vary throughout the day (they are highest in the early morning and lowest in the afternoon) and levels of thyroxine peak in the blood for a while after taking it, so if you have your test at the same time each day & take your thyroxine after the test that day you will get a better reflection of how you are responding to your meds as there aren’t so many variables. I have a reference for this somewhere but it’s late now & I’m off to get ready for bed so I’ll have a look another time.

Remind me if I forget!


You should definately be making a note of the ranges too. Take a look at Dr Toft's article in Pulse magazine.

Thyroid UK is writing a response to some parts of this article but some parts are good to show your GP.


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