Hi I just replied to an earlier post but thought it might be worth posting for a broader audience. I recently did a Blue Horizon test and was able to have my blood taken at my GPs' surgery by the nurse. It cost £10. The receptionist wasn't sure at first that it was possible but after research booked my appointment.
The nurse was surprised as she hadn't done it before but it all worked fine. I hope you can do the same.
It is up to the practice.
Darley Dale Medical Practice in Derbyshire said an unequivocal NO! They seem to be allergic to private tests, not quite sure what medication to give them 
So I am going to use nurse home visit for BH tests or phlebotomyservices.co.uk/wh... for the test that my Nutritional Therapist wants doing (with centrifuge preparation), as I am far away from places that would do blood draws, I have to use public transport and of course TFT has to be done early morning!
That's a real shame, maybe check around local surgeries and change if it's worth it!
It is a shame - I get through GPs and their practices like toothbrushes - going rogue now, its seems the only way to keep my sanity!
I've just checked with mine too and it was a definite no!!
I persuaded my surgery to take my blood for private testing at the same time as my annual Thyroid check. I waved the thyroid book by Dr Toft at the GP (never heard of him or aware of the book) and stated that I should have the full spectrum of tests and was prepared to pay if the NHS wouldn't test me fully. Probably won't happen again as exchange of complaint letters after dose halved on spurious data means that I am obviously not someone they want to help. Worth a try?
Self medicating T3 - GPs and NHS blood tests
private blood tests
NHS latest blood tests 
Private blood tests
Private blood tests 
