Blood test

[laurajj72]

I have been living with an underactive thyroid now for 8 years + I have recently gone up to 125 of levothyroxine but that was after someone told me i should not take my medication on the day of my blood test. Is this correct. I have never been given any Instruction on what to do as my doctor doesn't seem to know the answers. I have basically spent 8 years in the dark. Can someone please help me on this topic ?

[Bertwills]

Hello, the protocol that is recommended on this forum is to leave 24 hours after your dose of levothyroxine before your blood test. Also the test should be done as early as possible in the morning, before 9am. The reason is that TSH, thyroid stimulating hormone falls throughout the morning. Take your normal dose after the test is done.

If you’re being tested by the NHS this is likely to be the only test done. Therefore it’s really important to have its highest level recorded as your dose will be determined by it. In addition, you need to not eat or have anything but water to drink as eating also reduces TSH.

If you do private testing eg Medichecks, you will also have T4, levothyroxine & T3, Liothyronine levels recorded. This is preferable as it gives a better picture of how well the medication is working. The T4 has to convert to the active T3 & for some people this doesn’t work well leaving them still with symptoms.

[SlowDragon Administrator]

Bloods should be retested 6-8 weeks after each dose change or brand change in levothyroxine

For full Thyroid evaluation you need TSH, FT4 and FT3 tested

Also both TPO and TG thyroid antibodies tested at least once to see if your hypothyroidism is autoimmune

Very important to test vitamin D, folate, ferritin and B12 at least once year minimum

Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Looking at previous post you were taking omeprazole

Are you still taking this

Any PPI will lower vitamin levels further