Hello
I was wondering what a healthy 8 am fasting TSH in a 35 year old woman would be who is not on thyroid medicine? As long as the TSH is in the lab range (.45-4.50) and your free t4 is in range does that mean your thyroid is functioning appropriately?
Thanks
Depends on how you feel. Do you have symptoms?Ranges where a normal person can be but there is a win difference between one end of the range and another.
Maybe your normal is for example a TSH of say 1.25 and an Free T4 of 18. If your results came back with a TSH of 2.75 and a free T4 result of 12.5 (assuming these are in range) then your GP would declare that normal. But it is not for you.
As long as the TSH is in the lab range (.45-4.50) and your free t4 is in range does that mean your thyroid is functioning appropriately?
Not necessarily, no. If your TSH were 4.5, you'd be hypo. You're hypo when your TSH reaches 3. But, the NHS refuses to acknowledge that.
And, it would depend where the FT4 was in the range. If it were right at the bottom, then you would be hyp, no matter what the TSH. It's really not that cut and dried.
As for a 'healthy' morning TSH, I would imagine that's different for everyone. But, most euthyroid people have a TSH of around 1. Never over 2. The TSH is highest early morning, and drops throughout the day. So, later in the day, it would be lower than 1. 
Thanks for your explanation. I’m thinking of paying privately for my thyroid labs for TSH, ft4, ft3. You stated if FT4 was low then a person could be hypo with a TSH in range. Would you still be hypo if you had a high FT3 but a very low free t4? I believe that was what my test showed a few years ago and I think my TSH was around 2.5. I’ve had symptoms on and off since.
Would you still be hypo if you had a high FT3 but a very low free t4?
I don't think so. But, that would be highly unusual. Then again, you would need to take the TSH into consideration. The three results should be considered together, not individually. Normally, if the FT4 is low, the FT3 will be, too.
I believe that was what my test showed a few years ago and I think my TSH was around 2.5. I’ve had symptoms on and off since.
OK, well in that case, with a TSH that high, it would suggest that your thyroid was struggling, and making more T3 than T4 to keep you going. That does happen.
When did you last have a test?
Thanks. I’ll be having a private test in the next day or so and will post the results when I receive them. Thanks again for the info
Remember to have blood dawn at the earliest (make sure you are well hydrated a couple of days before). It is a fasting one but you can drink water and eat after blood is drawn.
it depends ... on where fT4 is in relation to TSH ,on how well you feel,
on whether TSH is rising or stable, and whether fT4 is falling or stable.
But mostly it depends on what your own 'normal' is .. if your normal TSH is 1 then you'll probably feel pretty bad at 4.49 and it might indicate a Thyroid problem even though GP might not agree with you until it's got much worse.
But if your 'normal' is 3 then 4.2 might just be the result of it being winter not summer, or just a normal temporary variation while the system rebalances itself to cope with need and you'd not have a thyroid problem at all.
This graph will give you an idea of what the most common 'normal' looks like (TSH around 1 or 2 ish )
healthunlocked.com/thyroidu...
Apparently in health our personal setpoint for TSH and fT4/3 levels doesn't change much over life , maybe a tad higher as we age ?
For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.
Also EXTREMELY important to test vitamin D, folate, ferritin and B12
Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies
About 90% of primary hypothyroidism is autoimmune thyroid disease
Ask GP to test vitamin levels and thyroid antibodies
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins
List of private testing options
thyroiduk.org/getting-a-dia...
Medichecks Thyroid plus antibodies and vitamins
medichecks.com/products/adv...
Thriva Thyroid plus antibodies and vitamins By DIY fingerpick test
Thriva also offer just vitamin testing
Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test
bluehorizonbloodtests.co.uk...
If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3
£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code
thyroiduk.org/getting-a-dia...
NHS easy postal kit vitamin D test £29 via
Median TSH graph of healthy population
Positive for antibodies TSH normal
High TSH but normal T4?
Is a TSH of 2.7 normal?
Why does TSH 
Normal TSH but low T4 
