Thyroid blood testing advice

[lilliebetfairies]

Thyroid blood testing

I have a memory that someone suggested that we stop thyroid meds pre test and then don’t eat before test. Is this right or am I mistak.

Thank you for your advice.

[shaws Administrator]

You are correct. Blood test is fasting and at the earliest: you can drink water and allow a gap of 24 hours between last dose and test. This is if you take levothyroxine and 12 hours if it is T3.

[lilliebetfairies in reply to shaws]

Thank you so much

[SeasideSusie Remembering]

Always advised here, when doing thyroid tests:

* Book the first appointment of the morning, or with private tests at home no later than 9am. This is because TSH is highest early morning and lowers throughout the day. If we are looking for a diagnosis of hypothyroidism, or looking for an increase in dose or to avoid a reduction then we need TSH to be as high as possible.

* Fast overnight - have your evening meal/supper as normal the night before but delay breakfast on the day of the test and drink water only until after the blood draw. Eating may lower TSH, caffeine containing drinks affect TSH.

* If taking thyroid hormone replacement, leave off Levo for 24 hours before blood draw, if taking NDT or T3 then leave that off for 8-12 hours. Take your thyroid meds after the blood draw. Taking your dose too close to the blood draw will give false high results, leaving any longer gap will give false low results.

* If you take Biotin or a B Complex containing Biotin (B7), leave this off for 7 days before any blood test. This is because if Biotin is used in the testing procedure it will give false results (Medichecks definitely use Biotin, they have confirmed this and the amount of time to leave the supplement off).

These are patient to patient tips which we don't discuss with doctors or phlebotomists.

[lilliebetfairies in reply to SeasideSusie]

Thank you so much