Your appointment

Allow up to 5 hours for your appointment.

Your test will take place at Kingston Hospital Outpatients Department, Level 4, Corridor E, Diabetes Day Unit.

Preparing for your test

Do not eat or drink

You must fast (avoid all food and drink) from midnight on the night before your test.

Medication

Read this information carefully before your appointment.

If you take:

medications containing biotin (usually multivitamin tablets or capsules).

7 days before.png

Stop taking these 7 days before your test.

If you take or use:

  • a regular dose of levothyroxine.

 

Do not take your usual dose on the day of your test.
If you take
  • any other tablets in the morning.
 Do not take your tablets. 
Bring them with you.

During your test

You can expect the following during your test.

  • We will ask you to lie on a bed. We will put a plastic tube (a cannula) into a vein in your arm. This will allow us to take blood samples.
  • After taking the first sample we will give you a dose of levothyroxine as follows:
    • If your BMI (body mass index) is more than 40: 1500 mcg
    • If your BMI is less than 40: 1000 mcg
    • If you are older than 65: 600 mcg
  • After giving you these tablets, we will take blood samples at 60, 120, 180 and 240 minutes.
  • During the test, we will monitor your blood pressure and heart rate every hour. 
  • When we have taken all of the blood samples, we will remove the plastic tube, and the test is complete.

Contact information

Kingston Hospital Diabetes Day Unit

Telephone:

020 8934 6370

Email: khft.dduadmin@nhs.net