What is Macro-TSH?

[mstsue]

I've been treated with varying doses of levo for about 2.5 years to treat hypothyroidism. I've just received blood test results that indicate I may have Macro-TSH. In searching for information, I'm turning up nothing except study results identifying the condition as "rare," but I can't find anything about it in normal human terms. Is anyone familiar with this?

[Jaydee1507 Administrator]

Welcome to the group. If you could complete your profile it helps members understand your thyroid journey so far and offer recommendations better. Click on your image icon to start.

Do you have a copy of your latest blood results that you can share with us? You are legally entitled to a printed copy of your results, ask at GP reception. In England you can get the NHS app and ask for permission to see your blood results on that by asking at GP’s reception.

We really need to see a copy of the results before we can comment.

Do you always take your levo on an empty stomach an hour away from caffeine drinks or food?

It's ideal if you can always get the same brand of levo at every prescription. You can do this by getting GP to write the brand you prefer in the first line of the prescription. Many people find that different brands are not interchangeable.

When hypo we get low stomach acid which means we cannot absorb vitamins well from our food, regardless of a great diet. For thyroid hormone to work well we need OPTIMAL levels of vitamins. Have you recently or could you ask your GP to test levels of ferritin, folate, B12 & D3? Private tests are available, see link for companies offering private blood tests & discount codes, some offer a blood draw service at an extra cost. thyroiduk.org/help-and-supp...

There is also a new company offering walk in & mail order blood tests in Crawley, Hove and Reigate areas. No charge for blood draw in clinic. Check to see if there is a blood test company near you. onedaytests.com/products/ul...

[jimh111]

TSH are a group of molecules with varying sizes and bioactivity. Macro TSH is a rare condition that produces large TSH molecules that have excess bioactivity.The TSH assay tells you how many molecules there are, it doesn't tell you how active they are. This is fine most of the time, especially in people without thyroid disease.

Sometimes the pituitary has subnormal TSH secretion, it secretes too little TSH (for given fT3, fT4) and the TSH has reduced activity, as evidenced by low fT3, fT4 with a normal TSH count. I believe this is a common cause of severe hypothyroidism that is not recognised.

In your case your TSH may be overactive. Who told you that you have macro TSH and do you have results for TSH, fT3 and fT4?

[radd]

mstsue

Welcome to our forum.  

If you have experienced unstable thyroid hormone levels I think they might be referencing chance of assay interference by macro TSH.

Can you post a photo of your results?

[tattybogle]

this is a bit old (2012), but seems to have a reasonably good explanation of what it is and what it means. academic.oup.com/jcem/artic... Since Macro TSH is a relatively new discovery , you may find more up to date information in more recent papers.

Basically if you have Macro TSH , you'll get incorrect/ unfeasibly high looking TSH results from most lab tests , so the TSH result is unreliable for those people and their fT4 and clinical symptoms are looked instead of using just TSH to monitor / diagnose thyroid problems .

[helvella Administrator Thyroid UK in reply to tattybogle]

Far from relatively new! This is a reference from 1963:

[Recent autoimmune research related to thyroid diseases. Presence of anti-TSH antibodies].

RIPA R , CARROZZINI B

Bollettino Della Societa Italiana di Biologia Sperimentale, 01 Feb 1963, 39:173-174

Anti-TSH antibodies attach to TSH and form a complex which looks like TSH to (some) tests , is called macro-TSH (or macro-thyrotrophin) and results in a higher TSH result than would otherwise be expected.

[tattybogle in reply to helvella]

my brain still thinks 2001 is 'the future' , then i look in the mirror .....lol

[jimh111 in reply to helvella]

Yes, I slipped up. I mixed up larger molecules due to glycosylation (more bioactive) and larger molecules (macro) due to binding to proteins or antibodies (less bioactive).

[helvella Administrator Thyroid UK in reply to jimh111]

Which is an important issue which is notable largely for the way almost everyone ignores it.

[jimh111]

My knowledge is too old! Macro TSH used to be used to describe TSH molecules with higher glycosylation, karger and more bioactive TSH. As others have noted it is now generally used to describe TSH molecules bound to antibodies that have reduced bioactivity and enhanced effect on the assays. In this case the TSH assay is misleading.

Either way you need to look at your fT3 and fT4 not the TSH result. More important is to look at signs and symptoms.

[mstsue]

Thank you for the helpful responses thus far. Here are my most recent results (also on the right you can see three previous results.) It's in Portuguese, but still pretty easy to interpret.

Results 06.2023

[Jaydee1507 Administrator in reply to mstsue]

Have you stopped taking your levo lately or started a PPI (for reflux/high stomach acid)? Have you started some different medicines or changed levo brand?

The result of your TSH seems compatable with your FT4 & FT3 which are both below range for some reason.

[mstsue in reply to Jaydee1507]

I haven't stopped taking Levo but I may have switched brands - I've never given that any thought. No other changes in health or other medications.

[Jaydee1507 Administrator in reply to mstsue]

Depending on where your Levo came from, I'd report it for subpotency and get some more of your usual brand ASAP. Whatever you are taking just isn't working and you need to restart ASAP, probably on 25 or 50mcgs and work back to your dose slowly.

[mstsue in reply to Jaydee1507]

Thanks. I am seeing my physician this week and will discuss.

[radd in reply to mstsue]

mstsue,

Both thyroid hormones are under range and TSH is way higher than one would expect given you are medicating. Do you feel symptomatic?

[mstsue in reply to radd]

Very tired 😔

[Jaydee1507 Administrator in reply to mstsue]

Also, just a tip when using this group. For someone to get a notification that you have replied you need to use the reply button directly below what someone has said. Currently you have been replying to yourself so noone knows that you have responded.

tattybogle radd jimh111 helvella

[tattybogle in reply to Jaydee1507]

mstue ... something had caused FT4 and fT3 to go over range in Feb test , so the fall in TSH at that test (from 4 to 0.07) was consistent with the higher levels of fT4/fT3 .

did anything happen before feb which caused this increase T4 /T3 levels ? did you have any symptoms of overmedication ? was dose reduced as result of feb test results ?

and now for some reason fT4 / fT3 are below range .. so a rise in TSH is to be expected .. whether TSH 71 is a 'much bigger rise than expected' is hard to say .

please can you translate these bits :

"Valor de TSH ......

<60% ....

resultado confirmado .....

[jimh111]

What dose of hormone are you on? Your TSH is reflecting your fT3, fT4 levels so I think you can ignore the macro-TSH stuff as it is very unusual to test for it. Thyroid function can be erratic during the first few years of hypothyroidism. How long have you been hypothyroid?

[mstsue in reply to jimh111]

Diagnosed about 2.5 years ago. I was on 25mcg for about 1.5 years, 50mcg for several months, then in February taken back down to 25mcg. Also, I had switched generic brands about 3 weeks prior to this most recent blood test.

[jimh111 in reply to mstsue]

Useful information. With these low doses you must still have some thyroid function remaining. Whilst under autoimmune attack the thyroid can erratically release thyroid hormone. Thus, you may be doing fine and then the thyroid dumps out some hormone. Your TSH drops and the doctor reduces your dose but once things settled down you are now on too low a dose. In this scenario the long term trend is usually for the thyroid to progressively fail.

Once the thyroid has packed in things become stable. However, for some people these fluctuations can be a problem. In this case they can use ‘block and replaced, you are given a drug to suppress the thyroid and a full replacement dose of thyroid hormone.

In the meantime you need your hormone dose increased to overcome your current hypothyroidism. If your levels keep jumping around you should ask about block and replace but for now I’d see how things go during the coming months.

I wouldn’t worry about macro-TSH, it’s quite rare and a complex subject. Just bear in mind that there’s a possibility your TSH isn’t accurately reflecting your status and concentrate on symptoms and fT3, fT4 instead.

[Jaydee1507 Administrator in reply to mstsue]

How have you felt on these different doses? I can only imagine you are feeing terrible at the moment.

I recommend following our thyroid blood test protocol to show stable blood levels of T4 in future.

Recommended blood test protocol: Test at 9am (or as close as possible), fasting, last levo dose 24hrs before the 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 just prior to blood draw can show a falsly elevated result and your GP/Endo might change your dose incorrectly as a result.

[helvella Administrator Thyroid UK]

If anyone feels the urge, there is what appears to be quite a decent slide show about macro-TSH.

It is quite a professional presentation - not easy to understand everything. If you don't get it first time, try again? Some of the pictures really do help.

slideserve.com/elysia/macro...

Jaydee1507 jimh111 radd tattybogle

[radd in reply to helvella]

So it's like a sandwich without a filling! 😬

[Brightness14]

Macro is a Greek word meaning Large that's all I know.

[euonymus]

In essence, macro-TSH means that the TSH assay doesn't work quite right for you, and that it comes up with an erroneously large number. You don't necessarily have a thyroid problem, just a testing problem, the way I understand it. In one case, the clinical biochemists involved had to resort to another test called "gel filtration chromatography". Here's the link: ncbi.nlm.nih.gov/pmc/articl...