Is fasting before blood test necessary

Hi

I am planning on doing a fingerprick test tomorrow morning. I haven't taken any medication today in readiness for the test. I didn't give fasting a thought! Do I also need to do this beforehand? Your advice would be greatly appreciated.

Thank youx

[humanbean]

Yes, you should fast. Don't eat anything from about now (10pm) until after you have got your blood sample. Also, don't drink anything except water.

Take your blood sample between about 7am - 8am, or at the very latest 9am. Whatever you do, try and keep the same conditions for thyroid testing from now on.

Take your thyroid meds tomorrow after you have got your blood sample. You should read all this tonight to help you prepare :

bluehorizonmedicals.co.uk/W...

[Hidden in reply to humanbean]

Thank you very much humanbean this is really helpful.

[SmallBlueThing]

Fasting for 12 hours or more causes a rise of about 20% in free T4, due to reduction in peripheral conversion to free T3. In one of his books, Dr Sarfraz Zaidi recommends fasting for six to eight hours before a test, which may also include cholesterol and blood glucose.

[Hidden in reply to SmallBlueThing]

Does this also apply to hypothyroid patients who are not making enough T4 on their own, but are on thyroid hormone replacement?

[SmallBlueThing in reply to Hidden]

Yes, it does. The book is Hypothyroidism & Hashimoto's Thyroiditis by Sarfraz Zaidi, and a large sample may be read via Google Books.

Many practitioners stress the importance of regular meals, yet there are followers of the intermittent fasting 5:2 diet who report improved thyroid function.

[Hidden in reply to SmallBlueThing]

Thanks, I will get this book as it sounds really interesting!