blood test differences.

[Yeswithasmile]

Hi.

I had some blood tests MMH usual conditions.

I also had some bloods done by NHS.

MMH

Ft4 16.9 (12-22)

Ft3 4.7 (3.1 - 6.8)

NHS

Ft4 18 (11 -22)

Ft3 5.3 (3.1-6.8)

Taken 26/7 hours after last dose of levo and 14 hours after lio

So, I am wondering why the NHS ones are higher considering I left well over time. Also I have a few symptoms that I have been putting down to menopause to be honest but as these results have just come through I am wondering if I need to alter my medication.

Typically I always go by my private tests and just raised t3 by 5mcg to 15mcg a day.

Any thoughts would be appreciated.

[Jaydee1507 Administrator]

Leaving longer than 24 hours for Levo & longer than 8-12 hours for Lio will give a false low result.

Are you taking any supplements, if so which?

What are your latest results for key vitamins - ferritin, folate, B12 & D3?

[Yeswithasmile in reply to Jaydee1507]

yes but it is higher than I expected. I wondered if anyone knew of any issues with MMH.

Thanks.

[Jaydee1507 Administrator in reply to Yeswithasmile]

You say you took one test under 'usual conditions'. What do you mean by that?

The other test you left longer than the recommended timings between T4 & T3 and blood test.

There are no issues with MMH. There was for a day or so a while back but all fine since.

It's quite possible to get different results from different labs. The FT4 range is slightly different between MMH & NHS.

When did you add 5 mcgs T3? How long ago?

[Yeswithasmile in reply to Jaydee1507]

usual conditions means no more than 24 hours after taking levo, nothing to eat and splitting t3 dose.

I added the t3 dose after the nhs blood test so it isn’t included in that. I was on Roma capsules for about a week before the MMH blood test and so 9 days for the nhs test.

I’m thinking that the nhs test is more likely at this point. I think, as I said below, the Roma ones work better or maybe is just an adjustment in brand, it’s giving me more ft4 🤷‍♀️ as I’m definitely much higher for ft3.

Oh it’s so tricky to judge but I’m grateful to everyone for allowing me to air my thoughts!

Thank you.

[Jaydee1507 Administrator in reply to Yeswithasmile]

I added the t3 dose after the nhs blood test so it isn’t included in that. I was on Roma capsules for about a week before the MMH blood test and so 9 days for the nhs test

Then no wonder you have 2 completely different test results.

You can only really get an accurate blood test after 6-8 weeks on a steady, consistent dose.

Recommended blood test protocol: Test at 9am (or as close as possible), fasting, last levo dose 24hrs before the blood draw, last T3 dose 8-12 hours before blood draw & no biotin containing supplements for 3-7 days (Biotin can interfere with thyroid blood results as it is used in the testing process)? Testing like this gives consistency in your results and will show stable blood levels of hormone and highest TSH which varies throughout the day. Taking Levo/T3 just prior to blood draw can show a falsely elevated result and your GP/Endo might change your dose incorrectly as a result.

[Yeswithasmile in reply to Jaydee1507]

it was the same dose just a swap from morningside to Roma.

[Yeswithasmile in reply to Yeswithasmile]

I added ‘another’ 5mcg after the blood test.

[Jaydee1507 Administrator in reply to Yeswithasmile]

It may even be the difference between the 2 brands.

Recommend you get full vitamin testing if you have remaining symptoms particularly.

[SlowDragon Administrator in reply to Yeswithasmile]

You need to retest 6-8 weeks after changing dose or change brand of levothyroxine or change of brand of T3

[SimLuc in reply to Yeswithasmile]

Isn't MMH manage my health, which is an NHS controlled service. Same as having the NHS deal with your blood tests, same NHS laboratory.

[Yeswithasmile in reply to SimLuc]

It is but usually you do get a discrepancy. Just not this much. But they were taken under different conditions so I was expecting the nhs ones to be far lower. That was my issue.

[helvella Administrator Thyroid UK]

I'm not aware of any MMH issues (though they did have some issues while back but that has been resolved).

Unlike all other tests, FT4 and FT3 tests demand special and essential requirements. They must be run at blood temperature (37 degrees), they must sample only a tiny quantity of the available T4 and T3 so as not to sample the T4 and T3 bound to the transport proteins, they must use the same chemical surroundings (for example, salt content, phosphate content) as is present in the blood, and they must work in the right acidity as present in the blood.

The failure of the development scientists to understand these special requirements, and the compromises needed to make the detection methods work, led to great variation in the performance of the FT4 and especially the FT3 tests between manufacturers offerings. For FT4 this is at present up to 40% difference and for FT3 60%. I would expect no more than a 5% difference as a reasonable variation.

thyroiduk.org/further-readi...

Your NHS FT4 is around 6.5% higher.

Your NHS FT3 is just under 13% higher.

So, not the 5% that would be expected if all was well in the world of testing, but much better than 40% or 60% as actually seen between manufacturers' systems.

(I have no idea if the labs involved use the same manufacturer's kit.)

[Yeswithasmile in reply to helvella]

thanks Helvella. That’s really interesting and helpful.

I admit, due to my symptoms and realising that I had a recent switch to Roma capsules I’m inclined to go with the nhs tests.

Even If these tests were conducted under the same conditions then I would still have never expected them to be bang on the same. I have usually done both at more or less the same time but never had such a wide variation.

I needed the nhs one for a prescription and was given a 9am slot. I did the other 2 days before (postal reasons and wanting to know if my correct dosing was off) exactly as I always have.

I am wondering if the Roma capsules are working better for me and so there’s more ft4 because I need a lesser dose now.

Thanks for the reply. It appears that AIT is the gift that just keeps on giving!!

[helvella Administrator Thyroid UK in reply to Yeswithasmile]

It is incredibly difficult for everyone. You seem to be making sensible choices, and trying to think things through.

Yes - Roma might be doing slightly more. Very difficult to know even with tests.

[Yeswithasmile in reply to helvella]

thanks Helvella. Appreciate that.

[tattybogle]

even if those tests were taken from the same blood sample.... (same day / same exact time, same lab / tested on two machines side by side .......the differences in those results are small.

fT3 43% (MMH) vs 59%... (NHS)

fT4 49% (MMH) vs 63% ... (NHS)

so you know your fT4 and fT3 are 'aprox mid range' .and you know your fT4 is a tad higher than your fT3.

honestly that is about as accurate a you'll get.. testing free T3 and free T4 is a very complex procedure. differences will always happen in testing . especially if you are using different assay machines from different manufacturers , which sometimes use different testing methods .

.... and if they were not taken from same blood sample (eg tested on different days) then that adds massively to the potential difference in results.... your blood levels will be different tomorrow than they were today.. and even on the same day , they will be different if tested an hour later.

The best you can do is use the same lab and test under same conditions to minimises the potential differences.

MMH did have some issues a couple a few weeks ago, can't remember the date , but they notified those involved ~ there were posts on here about it at the time .

[Yeswithasmile in reply to tattybogle]

thanks tattybogle. I appreciate your input.

Admittedly I have never done them on different days before like this or so much time after but I honestly expected them to be lower. I didn’t expect the discrepancy to be a higher one.

Having always done them back to back so to speak they have always varied but never a lot.

It has made me think I’m overmedicated so I am going to do as you suggest and get another test and do it in a few weeks and see.

Thanks ever so.

[SlowDragon Administrator]

Several members who have been changed from Morningside to Roma have found they don’t do well on Roma or can’t tolerate Roma at all

Were you getting 5mcg Morningside tablets?

Or cutting 20mcg tablets into 1/4’s to get 5mcg

Cheapest option by far for NHS is to get 20mcg tablets prescribed and cut up into 5mcg doses

Current prices here

healthunlocked.com/thyroidu...

[Yeswithasmile in reply to SlowDragon]

I suppose it’s early days for me then as I only swapped over a week ago.

I was on 2 x 5mcg morningside and have the same in Roma.

I have addressed the cost issue with my endo a couple of times but he never seems interested in the cost 🤷‍♀️