Do I take thyroid meds before blood test

[AngelaC66]

Hi All just a quick question. I have got thyroid blood tests in the morning at 9am I'm going early because also having a cortisol blood test and that's to be done at 9qm Apparently. Do I take my thyroid medication or not? It's a question I've wondered for a while. I would usually have my medication about 5am if I'm awake if not sometimes between 9 and 10am. I take 150 Levo and 12.5mcg of T3, I do usually take them together not even sure if I'm suppose to do that or wether I have to take separate. The main thing is do I take any of them in the morn. 😀

[Treepie]

No

[spongecat]

Take your Levo and T3 right after your blood tests.

[Phoenix605]

If you take your meds before you test then your FT3/4 will be artificially inflated. Thyroid tests should always be the earliest possible test and by 9 at latest to get highest TSH ( as that is what many GPs pay most attention to). It follows a circadian rhythm and drops through the morning.

You should also do a fasting test with water only until after the test, no supplements first either. Some labs use a biotin assay in the test so it is as well to leave out any supplement containing biotin for a few days to avoid it potentially skewing the results.

Gps say itdoesn't matter whether you have eaten, taken meds or test late. They are wrong, it can be the difference between a dose raise or cut sometimes if you tend to be borderline.

There is no problem taking your T3 and 4 at the same time but don't take supplements with them too as they can effect absorption of thyroid meds

[startagaingirl]

Hi - don't take them before. For future tests - too late for this one - you need to change your time of taking t3 beforehand so that it is ideally 12 hrs before test with down to 8 ok. 24 hrs is too long for t3.

[shaws Administrator]

The procedure for blood tests is the very earliest possible, fasting (you can drink water) and allow a gap of 24 hours from your last dose and the test and take levothyroxine afterwards. This keeps the TSH at its highest as doctors are apt to adjust dose due to the TSH alone and don't check any other important thyroid hormones.

[AngelaC66]

Thankyou all for your replies. Really appreciated

[startagaingirl]

That does of course just mean t4, the question also relates to t3.

[startagaingirl]

Standard advice and "policy" in this forum- as advised by all administrators and resident experts - is to leave gap of 24-36 hrs from last t4 dose before test and 8-12 (ideally close to 12) after t3 dose. Your advice is contrary to that and has the potential to cause confusion.

You are correct about doctors and their lack of knowledge, however we are where we are and all we can do is work the system as best we can with our superior knowledge!

Gillian

[AngelaC66 in reply to startagaingirl]

Right so when reading your time gaps between meds and blood test then I shouldn't be taking my T4 and T3 at the same time like I do is that right? 🤔

[startagaingirl in reply to AngelaC66]

It is no problem taking them together normally, I do. The only change is when you are going into a test. you really need to take t3 at night for a couple of nights prior, you can then revert to taking it in the morning again if that suits you.

This is because t3 hangs around in blood for a shorter time than t4, so to take it more than 12hrs before would give an inaccurate, probably falsely low, result for ft3.

Gillian

[AngelaC66 in reply to startagaingirl]

Oh dear well it's too late now. Maybe I should of sent this post last week 🙄 Thankyou for your advice

[AngelaC66]

I'm hoping to get on to NDT tbh reallyfedup coz I'm really fed up of Levi I think it's like poison