Blood test advice please: I'm currently taking... - Thyroid UK

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Blood test advice please

Rachel357 profile image

I'm currently taking 25mcg of Levo and wish to either switch to a NDT or wean myself off medication completely, depending on blood test results.

I have tried to book a blood test (to test TSH and freeT4) for as early as possible, but the earliest I am able to have is 9.10 as the nurses don't start work until after 9. I'm going to find it very difficult to fast beforehand as I need to eat within 30mins-1 hour after getting up, otherwise I feel very shaky and tend to feel ill the whole day. I have also read on here that it is recommended to have your blood test before 9. For my previous blood tests, I haven't fasted or stopped medication 24 hours before, as the nurse recommended me not to do so, also my appointments were always around 11am.

I'm also going to order a T3 test, as the lab refused to test this when requested by my doctor recently. I just wondered if it would be worth me ordering a finger prick test which tests TSH, FT3 and FT4? If I do this I don't know if I should choose the test which also tests T4 and antibodies. I had my antibodies checked last summer which came back as normal, so I don't know if I need to test these again?

Any help would be much appreciated. Thank you.

15 Replies
SeasideSusie profile image


What were the results that prompted starting you on 25mcg Levo?

How long have you been on it?

Why do you want to switch to NDT or come off thyroid meds?

If you can get a test at 9.10 that should be OK, my surgery doesn't do blood draws before 9am so I have to accept that. Fasting will give a higher TSH which is useful if you are looking for an increase in dose or to avoid a reduction.

If you do a private test with Medichecks or Blue Horizon, personally I would go for the one that does




TPO antibodies

TG antibodies

If you've had a negative antibody result before, it's always worth repeating because antibodies fluctuate and you may have had your previous test when they were low. A few negatives usually mean no autoimmune thyroid disease, if tested positive it doesn't need repeating.

If you've not had vitamins and minerals tested then it's worth doing those too as optimal levels are needed for thyroid hormone to work. Both companies do a test that I closed them.

Medichecks Thyroid Check Ultravit

Blue Horizon Thyroid plus Eleven

Hi, I started on Levo last January after my blood test which showed my TSH as 7.05 and Free T4 10.5. Before I was diagnosed, I had been vegan for a year and a half and during that time I hadn't taken an iodine or zinc supplement and I'm not sure if that's what caused me being hypo or chronic fatigue syndrome which I have had for about 8 years. After I was diagnosed, I started eating eggs and fish and other food high in iodine and I felt so healthy and had lots of energy. As soon as the Levo started kicking in, I started to feel very tired and felt like I had no energy to do things. This is why I wonder sometimes if I should have started on the Levo, as I might have got better naturally with a change of diet. I wish I had stopped taking it at that point, but I didn't realise at the time that it was an option, as my doctor said that I would have to take it for the rest of my life. I had also lost a lot of weight and felt very worried about my health.

After a few months on Levo, my TSH went down to 1.24. It was 1.57 in October and my T4 was 20.6.

I don't like taking a synthetic hormone and it makes me feel quite groggy, so i would like to switch to a NDT if my blood results show that I need to take something.

I might still have the blood test at the doctors and not fast, but stop medication 24 hours before, but I will ask if I can have antibodies checked too. Then order a T3 test. If I wasn't worried about money I would order a comprehensive test to test everything. I have had ferritin, folate and B12 tested at the doctors and these came back fine. I always take a vitamin D supplement everyday, so i don't know if I need to get this tested?

SeasideSusie profile image
SeasideSusieAdministrator in reply to Rachel357


25mcg isn't much of a dose of Levo. Have you always been on that dose or has it been reduced to that? It would be an idea to post your full results with their reference ranges. Normally, the aim of a treated hypo patient is for TSH to be 1 or below with FT4 and FT3 in the upper part of their reference ranges when on Levo. Without the range for your FT4 we don't know if that is over range (my lab's range is 7-17), or fairly near the top (Medichecks and BH range is 12-22) or even if it's middling with whatever your range is. And FT3 is needed to be tested at the same time as FT4 so we can see if conversion is good or not. No point in testing FT3 alone at a different time to FT4.

As for synthetic hormone, yes Levo is. But NDT isn't purely natural. Yes, it's made from pig's thyroid, but it's also full of synthetic fillers, you can't make tablets without them. Also, if you do need T3 added, it's a fixed amount in NDT whereas adding synthetic T3 gives more flexibility in the amount you can take.

Your GP may not be able to get antibodies checked again, but in any case the NHS only do TPO and you can be negative for TPO but positive for TG. So if you can get a Medichecks or BH test to include both of these that would be good.

Also, it's very important, when considering adding T3 in whatever form, to see nutrient levels, because if they're not optimal then conversion isn't going to be good so you wont know if you need NDT or T3 until nutrient levels are good. So although you say your ferritin, folate and B12 were tested by your GP and they came back fine, can you post the results (with ranges) because fine in your GP's opinion may not mean optimal that we need.

As for Vit D, yes you do need to test, and should have tested before starting to supplement. D3 is fat soluble and any excess gets stored, too much can lead to toxicity. You can do a home fingerprick blood spot test for £28 with City Assays

Also, there are important cofactors needed when taking D3

D3 aids absorption of calcium from food and K2-MK7 directs the calcium to bones and teeth where it is needed and away from arteries and soft tissues where it can be deposited and cause problems.

D3 and K2 are fat soluble so should be taken with the fattiest meal of the day, D3 four hours away from thyroid meds.

Magnesium helps D3 to work and comes in different forms, check to see which would suit you best and as it's calming it's best taken in the evening, four hours away from thyroid meds

Check out the other cofactors too.

Thank you for your advice, that is really helpful. I started on 50mcg. I only took it for one day and i felt unwell (heart palpitations etc), so I went back to the doctor and I was given 25mcg.

Is it okay to test TSH and FreeT4 on one morning and test FreeT3 the following day at the same time doing a home test?

I started taking vitamin D about a year and a half ago because I work from home and generally spend a lot of time indoors. I will definitely order a test to check my vitamin D level. I currently take Selenium, Vitamin B complex, Vitamin C and occasionally Magnesium if I'm feeling very stressed. I can only take a small amount of that (in powder form) as it makes me feel very drowsy. I have just started taking Zinc and Holy Basil, as my recent Cortisol test showed that my Cortisol levels are quite high in the morning and afternoons,

These are my recent test results:

Serum free T4 20.6 (12.00-22.00pmol/L)

Serum TSH 1.57 (0.27-4.20mu/L)

Serum Folate 20.0 (3.90-20.00ug/L

Serum vitamin B12 587 >180.00ng/L

I often wonder if I'm under-dosed as I get heart palpitations quite a lot, mostly when I'm tired or hungry. I also don't have much energy. I can go for quite long walks, but I struggle to do things like housework. I am used to this with having chronic fatigue syndrome, but I used to have more energy.

Rachel357 profile image
Rachel357 in reply to Rachel357

Just realised Ferritin wasn't tested for in my last blood test. Last March it was 26 (13.00 - 150.00ug/L)

SeasideSusie profile image
SeasideSusieAdministrator in reply to Rachel357


Your ferritin was very low but probably your GP wouldn't do anything about it as it's in range. It would be worth checking it again to see if it's lower, low ferritin can suggest iron deficiency anaemia which would need to be treated.

I don't suggest iron supplements because there's more to it than just ferritin, a full iron panel would give a better picture.

For thyroid hormone to work (that's our own as well as replacement hormone) ferritin needs to be at least 70, preferably half way through range. You can help raise your level by eating liver regularly, maximum 200g per week due to it's high Vit A content, and including lots of iron rich foods in your diet

SeasideSusie profile image
SeasideSusieAdministrator in reply to Rachel357


It's really better to do all tests from the same blood draw, it will give you the most accurate levels from which you can see your conversion.

Medichecks do

FT3 at £29

TSH/FT4/FT3 at £39

TSH/FT4/FT3/TPO/TG antibodies at £59

To be on only 25mcg and have these results

Serum free T4 20.6 (12.00-22.00pmol/L)

Serum TSH 1.57 (0.27-4.20mu/L)

is quite remarkable! It would be interesting to see if your FT3 is in balance or whether your conversion is good enough.

Folate is good and B12 isn't bad, but an extract from the book, "Could it be B12?" by Sally M. Pacholok says:

"We believe that the 'normal' serum B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebrospinal fluid below 550".

"For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1000 pg/ml."

so I keep mine at around 1000.

I did take Levo about 4 hours before the blood test, so I don't know if that would have affected the results?

What do you take to maintain your serum B12 levels at 1000? Thank you.

SeasideSusie profile image
SeasideSusieAdministrator in reply to Rachel357


Taking your Levo 4 hours before your blood test will have given you a higher FT4 than leaving it off for 24 hours, but I don't think the difference would be massive.

My original B12 result was a bit higher than yours. I used 1 x 1000mcg sublingual methylcobalamin lozenges daily then when I retested a few months later it showed just over 1000 so I reduced the methylcobalamin lozenges to 1 x 4 or 5 times a week to maintain that level. Testing when supplementing won't give a base result to show what you are holding on to (you need to be off it for 4-5 months) but it does show if you're taking enough for the level you want to be at.

SlowDragon profile image
SlowDragonAdministrator in reply to Rachel357

When you say ferritin, folate, B12 and vitamin D are fine, can you post actual results and ranges

You may be in range, but that's not the same as optimal levels

25mcg is extremely small (usually far too small) dose

Rachel357 profile image
Rachel357 in reply to SlowDragon

Thank you. I have just posted my results and ranges in the comment above.

SlowDragon profile image
SlowDragonAdministrator in reply to Rachel357

There's no vitamin D results

You can get test from

£28 postal test

Looking to be around 100nmol

B12 is mid range

Folate looks good

Ferritin needs to be at least 70

Eating liver once a week would help, or iron supplements, taken with vitamin C to aid absorption

Rachel357 profile image
Rachel357 in reply to SlowDragon

Thank you. I will get an Iron supplement.

SlowDragon profile image
SlowDragonAdministrator in reply to Rachel357

See SeasideSusiedetailed vitamin advice on many of her replies

Rachel357 profile image
Rachel357 in reply to SlowDragon

Thanks. Do you think I should test Ferritin again before getting a supplement, as I haven't had that tested since last March?

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