bethm1983 It's hard to say as you've not given any information. Are you diagnosed Hypothyroid and on any thyroid meds? If so what dose?
Hard to comment on FT4 without a range, it could be at the bottom of the range, it could be below range. You need to ask for the range, either from your surgery or from the lab that did the test.
OK, so TSH is within range but showing signs of struggling to be 2.57. I think your FT4 is either very low or possibly under range. In either case it shows you are producing very little thyroxine yourself - this is why you need the range to see exactly where you are. If it is low or under range then your body is doing it's best to produce some T3 which is the active hormone that every cell in our bodies need. Eventually this will reduce as well.
You could do with having thyroid antibodies tested. There are two types, Thyroid Peroxidase (TPO) and Thyroglobulin (TG). The NHS rarely does TPO and almost never does TG but see if you can get them done.
A hypothyroid diagnosis is very rarely given until TSH reaches 10 but if there are antibodies there's a slight chance you may be prescribed Levo.
Also, ask for vitamins and minerals Vit D, B12, Folate and Ferritin.
Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. Both companies often have money off offers on.
DIY finger prick test or option to pay extra for private blood draw.
All thyroid tests should be done as early as possible in morning and fasting. This will give the highest TSH, which is as you have discovered all many GP's incorrectly look at.
When you get retest come back with a new post for advice on how to proceed.
Meanwhile read posts on here, & the main site Thyroid UK to learn as much as possible
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.