Hello, I have a question......I’m getting my bloods done on Thursday (full range to see where I’m at) and it’s often crossed my mind why we stop taking our Thyroid medication before hand.
I’ve been on Levothyroxine for 26 years now and I will no doubt be on it for the rest of my life. So, really I want to see that the dose I am on is working well for me in getting my levels as best they can be. If not, then I will need to adjust.
If I come off of my Levo 24 hours before, surely that then doesn’t show how the Levo is doing for me at that moment?
Apologies if I’ve missed the point and I’m sure someone will put me straight, but I have tried to rationalise it, and don’t quite understand. Thank you in advance for any replies. Mandy
Written by
Mandy2007
To view profiles and participate in discussions please or .
When we have our thyroid tests, we want to measure the normal amount of hormone circulating and depending on the result of that the GP will decide if a dose adjustment of our hormone replacement is necessary. Very few GPs seem to take into account any symptoms we may be expriencing so we are pretty reliant on our test results.
If we take our hormone replacement too close to the blood draw, both Levo and T3 peak in the blood 2-4 hours after ingestion. T3 is quick acting and leaves the blood after 12 hours. Levo takes longer.
So if we take our dose too close to the blood draw we will be measuring the dose just taken and the result will come back with a false high and the GP may reduce our dose.
Similarly, if we take our dose too far away from the blood draw, we get a false low result.
So to get a result reflecting the normal amount of circulating hormone it's advised to take last dose of Levo 24 hours before the blood draw, and last dose of T3 (or NDT) 8-12 hours before the blood draw.
Measuring the amount of hormone in our blood only shows what's in the blood, it doesn't show what's in the cells (that can't be measured), so really the blood test isn't even a good indicator because it's the amount of hormone in the cells that matter.
This is great advice that I recommend. I took my levo in the morning per usual and then had blood drawn 4-5 hours later and T4 was falsely high (I assume T3 May have been as well).
Levothyroxine is a synthetic and inactive hormone (also called T4). It should convert to liothyronine (T3) and it is T3 that is the Active hormone and is needed in our millions of T3 receptor cells, the brain and heart contains the most.
The half-life of T3 is 24 hours in the blood. It doesn't 'leave the blood' in 12 hours. And, what gets into the cells stays there for about three days.
The predominance of Hashimoto thyroiditis represents an interesting finding, since it has been indirectly confirmed by an Italian study, showing that autoimmune thyroid disease is a risk factor for the evolution towards NCGS in a group of patients with minimal duodenal inflammation. On these bases, an autoimmune stigma in NCGS is strongly supported
In summary, whereas it is not yet clear whether a gluten free diet can prevent autoimmune diseases, it is worth mentioning that HT patients with or without CD benefit from a diet low in gluten as far as the progression and the potential disease complications are concerned
Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies
While still eating high gluten diet ask GP for coeliac blood test first or buy test online for under £20, just to rule it out first
Assuming test is negative you can immediately go on strictly gluten free diet
(If test is positive you will need to remain on high gluten diet until endoscopy, maximum 6 weeks wait officially)
Trying gluten free diet for 3-6 months. If no noticeable improvement then reintroduce gluten and see if symptoms get worse
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Stopping B12 before blood test? 
Take levo before or after blood test?
Levo before blood test?
When (if?) to take levo before blood tests please?
Taken Levo 17 hours before blood draw by mistake 
