Advice

[cahod6103]

Hi can anyone tell me if mU/L is the same as mlU/L . Please and thanks. I’ve had had NHS thyroid tests and Private ones and they are quite different one TSH is in mU/L other in mlU/L, but levels are quite different.

[SeasideSusie Remembering]

mlU/L = milli-international units per Litre

mu/L = milliunits per litre

I believe they are the same.

Don't worry about the units of measurement for TSH. Look at the ranges and where your result lies within that range - that tells you what you need to know.

If your results are different, it could be that the test was done at a different time of day - time of day affects TSH. Eating can affect TSH. Caffeine containing drinks affect TSH.

If you post both results, with reference ranges, we can comment.

[cahod6103 in reply to SeasideSusie]

Thank you, I will post both sets for you to have a look at.

[cahod6103 in reply to cahod6103]

NHS results were in mU/L for TSH

Free T4 - 13 ref range 11- 27

TSH - 2.6 ref range 0.3 -5.0

Total T3 - 1.8 ref range 1.3 - 3.1

No free T3, they only do total T 3 for some reason.

Private results from Thriva were

TSH - 4.79 ref range 0.27 - 4.3

Free T4 - 12.4 ref range 12 - 23

T3 - 3.85 ref range 3.1 - 6.8

[cahod6103 in reply to cahod6103]

I forgot to say there was 4 weeks between these tests, NHS was at about 12.15 after eating and having medication, Thriva was done at around 8.30 am, had no medication or anything to eat.

[SeasideSusie Remembering in reply to cahod6103]

cahod

NHS: Total T3 - 1.8 ref range 1.3 - 3.1

Thriva FT3 - 3.85 ref range 3.1 - 6.8

These can't be compared.

**

NHS: TSH - 2.6 ref range 0.3 -5.0 = 49% through range

Thriva: TSH - 4.79 ref range 0.27 - 4.3 = 112% of range

NHS: Free T4 - 13 ref range 11- 27 = 12.5% through range

Thriva: Free T4 - 12.4 ref range 12 - 23 = 4% through range

Questions to ask are

1) Were you on the same dose of thyroid meds for both tests?

2) What time did you take your thyroid meds before both tests?

3) Did you take both tests under the same circumstances, ie.

* Were they both done at the same time of day - what time? Best time is no later than 9am.

* Were they both done fasting - when did you last eat befor the tests?

* Did you drink water only before the tests?

4) Were you taking prednisolone when both tests were done?

[cahod6103]

Yes I was on same doses both tests, I had the NHS test at about 12.15 to 12.30, had medications beforehand, and had eaten beforehand and had a decaf coffee . Thriva test was at about 8.30 am, had no medication, nothing to eat, only had a little water. I wasn’t taking Prednisolone at the time of the NHS tests, but was with the Thriva ones, there was a month between the two tests, NHS one was on 4th Jan, Thriva was on 7th Feb.

[SeasideSusie Remembering in reply to cahod6103]

I didn't get notification of your reply because you didn't reply directly to me, you need to use the blue "Reply" directly below a member's message for them receive notification.

Because you didn't do both tests under the same conditions you can't compare the results.

The lower TSH with the NHS test is because it was taken at close to the time of day when TSH is lowest (1pm). TSH is highest from midnight to 4am and lowers throughout the day, lowest at 1pm then gradually rises again. Your Thriva test was done at the time we always advise - no later than 9am to give the highest possible TSH.

Eating can lower TSH so possibly another reason contributing to why your NHS result is lower.

FT4 is higher with your NHS test because you had taken your Levo before the blood draw. There should be 24 hours between last dose of Levo and blood draw.

As you weren't taking prednisolone when the NHS test was carried out but were when you did the Thriva test, this may have made a difference, but what that might be I don't know.

[cahod6103 in reply to SeasideSusie]

SeasideSusie thank you for all your help, this is all so confusing, but the worst bit is I’m feeling so unwell. My next NHS test is beginning of March, but the Endo only wants TSH tested this time , I feel that’s wrong as I’ve only had one increase of t3 since I started on it, and at that time he said he wanted all 3 levels checked every 6 weeks, but he seems to have went back on that now. My appt for bloods next time is at 11.30am, should I take my meds after that ? Thank you.

[SeasideSusie Remembering in reply to cahod6103]

cahod

I think you need to clarify things with the endo. If he said he wanted all 3 levels checked every 6 weeks then remind him and ask why it isn't being done. Who is supposed to be doing the 6 weekly checks? If you don't see the endo every 6 weeks are you supposed to be having them done at your GP's surgery? If so then take control and book them yourself. Make sure that the blood form states "patient on T3" and that FT3 is requested along with TSH and FT4. If it doesn't get done, speak to your GP and say your endo insisted these 3 tests were to be done every 6 weeks and get your GP to contact the lab and insist they're all done.

My appt for bloods next time is at 11.30am, should I take my meds after that ?

If you think you will be having a blood test at that appointment, then don't take your meds until afterwards. Time the previous day's meds so that you get the correct time gap between last dose and blood test - Levo 24 hours, T3 8-12 hours.

[cahod6103 in reply to SeasideSusie]

SeasideSusie thank you. I spoke with my GP, they are asking for T3 and t4 plus TSH to be tested on the form, wrote that results are for the Endo as I’m on a trial of T3, but last time labs only checked TSH, wouldn’t do others because it was in range ! Consultant has seemingly agreed with them, and that’s why I got a letter saying at start of March it would only be TSH being checked, but I don’t think that’s fair. I still have the piece of paper he gave to me at my first appt, stating that all 3 levels had to be checked every 6 weeks, and to phone his secretary and give her the results, so that he could then change dosages if needed. I’ve only had t3 increased once, that’s in 6 months. I don’t think he should have changed his mind as he surely can’t get a true picture from the TSH alone.

[SeasideSusie Remembering in reply to cahod6103]

Consultant has seemingly agreed with them ... I don’t think he should have changed his mind

I think you need to get that from the horse's mouth.

I would contact the endo's secretary, or see if you can speak to the endo himself, and try to get this sorted. When on T3 it's essential to test FT3, otherwise how on earth are they going to know how you are doing, what progress (or not) you are making, if you are on the right dose or need it adjusting. It's must madness.

[cahod6103 in reply to SeasideSusie]

Yes, that’s what I feel too, I’ll phone her tomorrow and she can at least pass a message on if I can’t get speaking to him. Thanks .