Levo before blood test?

Hi all,

I was diagnosed with hypothyroidism 8 weeks ago and have been taking 25mg of Levo since, which I normally take around 7.30am. I have a blood test this week at 10am, should I take my dosage as normal in the morning, or later on? I've read different things saying that you should and shouldn't take it before.

Also, please could someone tell me exactly what I should be asking for them to test? My TSH was only 6.5 when I started treatment, and my doctor didn't seem particularly bothered when I had a follow up appointment and asked about T3/T4/vit D etc.

Many thanks for your help, still trying to get my head around it all!


9 Replies

  • If you have the blood drawn within a few hours of taking levothyroxine, you will be measuring the peak caused by taking the tablet. Delay taking it until after the blood has been drawn. This tends to affect FT4 and FT3 tests - TSH is slower at changing. But you can never be sure what they will test for!

    Non-thyroid tests should, in my book, include vitamin B12, folates, iron/ferritin and vitamin D. Also a Full Blood Count.

    You will be lucky if you can get tested for FT4 and FT3, though logically it would be appropriate.


  • Thank you, that's really helpful. I'll see how far I get! I don't feel a lot different after 8 weeks, so I'm interested to see how things have changed on paper at least.


  • 25 micrograms is a very small dose and few people remain there!


  • Your dose is so low and should have been increased at least by week 6, if not week 4. Always get a copy of your thyroid gland blood test results and keep for your own records. They must have the ranges too as labs differ. You can then post them here if you have any queries.

    Also, if not already done, have a vitamin B12, Vit d, ferritin, folate and iron tests too.

  • Thank you. I went back to the doctor as instructed after 6 weeks and said I didn't feel much better but she didn't seem too concerned and said to just wait and see what this test shows. I asked about T3 and T4 but she said the lab only report them if they're abnormal so I guess mine weren't. I also asked about antibodies and she said they were slightly raised a year ago (but normal TSH) so hadn't been repeated. That's fair enough, but it would have been nice to know the cause 8 weeks ago! She hasn't said hashimoto's but I'm assuming that's what she means.

    Sorry, that's turned into a bit of a ramble!

  • I hope she increases soon. She maybe doesn't know, but you should aim to have a TSH 1 or below. She will make you more unwell if she insists on a TSH at the reference range.

  • I went for my blood test this morning, they will just look at TSH. I asked about other things, but the nurse said the doctor hadn't asked for anything else so she couldn't, and that I had a lot of things checked a year ago when I had a borerline thyroid result (B12, D, calcium etc) which were all ok. That's fine, but I just wondered how often you might expect those sorts of tests to be repeated as presumably things can change?

    Many thanks

  • It is now customary for Labs to do no other tests even if requested by GP if your TSH is in range.

    If you are on levo and are stable the usual check up is once a year. If you feel unwell they should take a blood test earlier.

    Get a copy of your blood tests you had 5 days ago from the surgery - you are entitled and post them on a new question as I am not able to access the site regularly as am away from home at present. Also ask if they can give you a copy of last year's blood tests, B12, etc. as you may be low on these although 'within the reference range'.

    Best wishes

  • Thanks for your message, my tsh was 2.3 this time, but I'm still not feeling A1. I posted a question about it on fri and have had some helpful responses including being firm with the GP!

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