Medichecks test

[sweepandollie]

I have a Medichecks kit but unfortunately the clinic I am supposed to go to can’t take my blood until 11 am. The nurse practitioner said she had been taking blood for 30 years both privately and NHS and you only have to fast for 14 hours beforehand. How much will 2 hours skew the result?

[helvella Administrator Thyroid UK]

The main issue isn't fasting. It is that TSH falls from the early hours through to the afternoon. Have a look at this paper:

academic.oup.com/jcem/artic...

(Fasting is just a secondary issue.)

[SlowDragon Administrator]

You don’t need to fast as such….but it’s recommended to test thyroid levels just before 9am to get highest TSH and last dose levothyroxine 24 hours before test

To not drink or eat anything other than water between getting up in morning and blood test

Then take your daily levothyroxine immediately after blood test

Looking at previous post….your GP making fuss over mildly reduced TSH …..so you do really want early appointment if at all possible to get highest TSH

[SlowDragon Administrator]

More expensive option…..a nurse to your home to do blood test

But you would need to insist appointment was 9am

[SeasideSusie Remembering]

sweepandollie

Which test are we talking about? Certainly we don't say fast for 12 hours for a thyroid test but if doing an iron test then fasting for up to 12 hours is mentioned by the NHS:

nhs.uk/common-health-questi...

Common fasting blood tests

Examples of blood tests that may require you to fast include:

a fasting blood glucose test (used to test for diabetes) – you may be asked to fast for 8 to 10 hours before the test

an iron blood test (used to diagnose conditions such as iron deficiency anaemia) – you may be asked to fast for 12 hours before the test