TESTING QUESTION

[Henson1980]

Hi, I stopped taking my levo Saturday and Sunday as I was going to do a home thyroid test this morning but I didnt have time to do it so my question is, if I miss another dose tonight and do the test first thing tomorrow am I going to get an inaccurate reading? Trying to avoid my levo being increased unnecessarily. I stopped Biotin a week ago as well.

[SeasideSusie Remembering]

Henson1980

if I miss another dose tonight and do the test first thing tomorrow am I going to get an inaccurate reading?

Yes, and you were going to get an inaccurate result anyway because you stopped your Levo too early even if you'd done your test today. Last dose of Levo should be 24 hours before the test, any longer and you get a false low FT4 result. So if you had done your test this morning your last dose should have been yesterday (Sunday) morning not miss Saturday's and Sunday's doses.

If I were you I'd abandon your test this week, get back on track with your regular Levo dose and do the test next week and only leave 24 hours between last dose and blood test.

[Henson1980 in reply to SeasideSusie]

Thank you for the swift response. Ahh ok, I was on the understanding you stop 48hrs before not 24, silly me! Advice noted, I will get back on the levo and do the test Monday.

[tattybogle]

if you want a realistic fT4 result last dose Levo should not be much longer than 24hrs before test , so missing Saturdays does was not correct . Eg for a test on monday morning at 9am , if you normally take your levo in the mornings, you would take saturdays and sundays doses as usual , and then take mondays dose after the test.

If last dose was sometime on friday and you don't test till tuesday then the fT4 result you get will be quite a lot lower than what your 'real' fT4 level is on your dose. This will cause fT4 to be lower, and such a long gap may even cause TSH to go up a bit too .

Did you mean to write ' trying to avoid Levo increased unnecessarily' ?

That doesn't make sense ..... leaving too long between levo and test will be more likely to cause them to increase dose.

Did you mean 'trying to avoid a decrease ' ?

[Henson1980 in reply to tattybogle]

Thank you. Sorry what I meant was, I didn’t want to test tomorrow if it was going to affect the result. I’m going to do the test next Monday now as Iv messed it up and need to get my levo back on track

[SlowDragon Administrator in reply to Henson1980]

Do you normally take levothyroxine waking or bedtime?

If you normally take levothyroxine waking, just delay dose until after blood test

If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test

If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning.

Delay Sunday evening dose levothyroxine until after blood test on Monday morning.

Take Monday evening dose levothyroxine as per normal

This ensures 24 hours between last dose levothyroxine and test

Take both doses of levothyroxine that you have missed

What vitamin supplements are you currently taking

Remember to stop taking any supplements that contain biotin 5-7 days before test (eg vitamin B complex)