Hello ,my GP has rung me up because my recent blood test is unusual ,my T4 and my TSH are both low so she has to speak with a endocrinologist for advice on this as she has never come across this before.
Has anyone ever been told this and what does it mean .
Do you have the actual numbers? 'Low' is a very broad description. 
No I don't have the numbers ,the gp just rang up to say she needs advice from a thyroid specialist
OK, well, go along to the surgery and ask the receptionist for a printout of your results. It is your legal right to have a copy. You need to keep your own records for future reference.
I'm like greygoose - I'd like to see the actual numbers and reference ranges, because what a doctor means by normal, high, and low isn't necessarily the same as what a patient means by the words normal, high, and low.
If the results for TSH and Free T4 really are low then it is possible you have a condition called central hypothyroidism, or more specifically, either secondary or tertiary hypothyroidism.
In primary hypothyroidism (the most common kind), it is the thyroid gland that fails.
However the output of the thyroid gland is controlled by the pituitary, and the output of the pituitary is controlled by the hypothalamus. Both the pituitary and the hypothalamus are in the brain and they can be damaged by head injury, whiplash, and/or disease.
If the pituitary doesn't work well then this could cause secondary hypothyroidism.
If the hypothalamus doesn't work well then this could cause tertiary hypothyroidism.
In all cases of hypothyroidism the treatment is the same - replacement of the missing thyroid hormones.
If you aren't taking T3 or NDT, it usually means that you have secondary/central hypo. It's not unusual, but GPs don't know what to do about it. It means that either your hypothalamus or pituitary aren't working well, so the signal to produce TSH doesn't happen or get through. Therefore, your thyroid doesn't know it should produce more T4 and T3 - so: low everything. I have it.
If you are taking any med containing T3, it's just normal and the GP is not clued up.
Thankyou every one it's so confusing ,I have been on ammitryptline for about 10 yrs for fybromyalgia , then someone told me it's underactive thyroid that's causing my symptoms ,so I asked GP for blood test which came back normal ,then someone gave me a number for Dr skinner ,who told me I have the classic symptoms of underactive thyroid ,of course my doc called him a quack and not to take thyroxine ,but I managed to get some through Dr skinner .
Then we moved to Cyprus I only had to see a doc there and he pescribed for me what I was already on (thyroxine and T3 ,started to feel better for the 8 yrs we were there,then we moved back registered with a gp ,and guest what they said I need to reduce the thyroxine because if I didn't I would have a heart attack ( blood test came back ,apparently I was taking too much thyroxine ha! Ha !..
I had to come off T3 then next blood test I needed to reduce thyroxine etc etc so I started ordering my thyroxine from the pharmacy in cyprus where we lived ,I then refused to have blood tests until now ,we were applying for life insurance for a mortgage so I stopped taking thyroxine until after the blood test ,and this brings me to how I am now ,no thyroxine in my system that's when the gp rang me to say Imy TSH and T4 are low and she doesn't understand it ,even though I have kept her up to date what's been happening .
I am really confused and it doesn't take much while I am not on thyroxine ,my gp also said she really needs to find out wether I need thyroxine in the first place .
Jill
Ah, OK, well, if you've been taking T3, the TSH could take a while to come back up. Or it might never come back up. Your HTP axis could have been deregulated. And, unless you find a doctor capable of understanding that, I don't know what you can do.
TSH is irrelevant at its lowest levels.
Stelladog1,
Agreeing with greygoose, humanbean and Angel_of_the_North - the flowchart here:
thyroidmanager.org/algorith...
Shows that low FT4 and low TSH together have one cause - hypopituitary. (Though the next question should be to ask whether the hypothalamus is causing that, or not.)
There are other causes for low FT4 and normal-to-low TSH - other medicines, illnesses and specifically non-thyroidal illness syndrome. (The flowchart is a bit cryptic. 
)
TSH low but T4 low?
Low t4
New here, undiagnosed, Normal TSH Low T4
Low TSH
T4 Only, Low TSH
