IGF-1 Blood Test: I have had the results of my... - Thyroid UK

Thyroid UK

138,939 members163,039 posts

IGF-1 Blood Test

AppleOrchard profile image
19 Replies

I have had the results of my IGF-1 blood test. It’s 26.4nmol/L. The endo has said he thinks it’s because I’m over medicated with my thyroid medication. He’s arranged an OGTT.

I’m currently on 75mcg T4 and 10mcg T3. I recently lowered the dose from 100mcg/10mcg. I had been on that dose for a long time. I added in T3 in February 2022. My TSH is always suppressed.

The blood tests are always done as per this group.

Results:

FT3

Range: 3.1 to 6.8

2 April 2024 5.7 pmol/L

30 November 2023 5.8 pmol/L

27 October 2022 5.9 pmol/L

8 June 2022 6.5 pmol/L

1 February 2022 4.2 pmol/L

FT4

Range: 12.0 to 22.0

2 April 2024 21.3 pmol/L

6 March 2024 18.3 pmol/L

30 November 2023 23.2 pmol/L

18 September 2023 20.3 pmol/L

9 May 2023 19.8 pmol/L

27 October 2022 21.1 pmol/L

8 June 2022 14.0 pmol/L

12 May 2022 13.4 pmol/L

1 February 2022 25.5 pmol/L

Could it be Thyroid?

If not thyroid, what could it be?

I’m under investigation for adrenal insufficiency which is why this test was done.

Thank you very much!

Written by
AppleOrchard profile image
AppleOrchard
To view profiles and participate in discussions please or .
Read more about...
19 Replies
greygoose profile image
greygoose

IGF 1 is used as an indicator of HGH levels, as it appears it's not easy to test the HGH itself. Although that does seem to be done more often these days.

So, if a pituitary problem is suspected that's one of the tests they do because HGH is a pituitary hormone. However, that seems like a rather round about way to test for adrenal insufficiency! Why didn't they just test ATCH, which is what stimulates the adrenals to make cortisol.

Sorry, but that is a terrible way to lay out your blood test results because we need to see the three results - TSH, FT4 and FT3 - done on the same day, together, to understand them. And, you haven't even given any TSH results. So, do you have a thyroid diagnosis of some sort? Do you have Secondary Hypo (i.e. where the pituitary is the problem).

The problem with testing HGH via IGF1 is that different things can affect IGF1 - like vit A deficiency - that don't necessarily affect the HGH itself. And vice versa. HGH needs good levels of T3 for the pituitary to produce it. IGF1 doesn't.

What's more, you haven't given a range for the IGF1, so we can't see if that is high or low. If it is low, then your HGH will probably be low - but not necessarily. So, I would disagree with your doctor that your IGF1 level is due to being over-medicated, which you aren't, anyway.

But, none of this has much to do with adrenal insufficiency. So, either your doctor hasn't a clue what he's doing but is trying to be clever, or, I'm missing something here! 🤣

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you very much for your detailed reply. The whole HPA-axis and endocrine system seems so complicated!

I’m sorry for doing the blood tests the way I did. It was simply to see if there’s any over medication. The endo thinks I’m over medicated. I do not believe I’m over medicated at all.

I am UAT and have been since 2004. I saw Dr Toft from 2004 until he retired in 2018.

My current endo prescribes T3, but does not test it when doing blood tests.

I reduced my T4 down to 75mcg from 100mcg. I maintained the T3 at 10mcg. The endo wrote to my GP asking for the TSH and T4 to be tested in six week. There was no mention of T3.

I have had my cortisol levels checked and an SST done. I had to request the ACTH.

SST 15.04.24

Baseline cortisol 175 nmol/l

30 minutes 372nmol/l

60 minutes 454 nmol/l

ACTH 02.05.24 (7.2-63.3) / Cortisol

11.6ng/l / 228nmol/l

I was highly stressed when this test was done.

I don’t have a range for the IGF-1 but the endo said it’s slightly raised so I’m having the OGTT.

I am not sure why he tested the IGF-1!

I called the Pituitary Foundation after the results of my SST and the person I spoke to said that the consultant should not have sent me away saying he’d see me in a year. He said the results are indicative of adrenal insufficiency.

I don’t think the endo has a clue what he is doing. I have asked for a referral to a different endo in a different hospital. I am waiting to hear back.

I’m including some of the tests that were done.

Thank you again for your reply.

Recent test results
greygoose profile image
greygoose in reply to AppleOrchard

Well, those tests are a bit of a jumble, aren't they. lol

In the first lot of results your FT4 is slightly over-range, but that was probably because of poor conversion - although without an FT3 result we cannot tell how well you convert. How did your endo know you needed T3 if he doesn't test it?

The TSH is low but then it would be with that high FT4.

Your ferritin is too low.

In the second group of tests everything is low. But difficult to tell how low your cortisol is without a range. But, I wouldn't have thought it was low enough to constitute adrenal insufficiency - adrenal fatigue, yes! And that wouldn't be surprising in a hypo.

And in the third group, your folate is good but your B12 is dangerously low. Have you been tested for Pernicious Anemia?

So, you didn't say if you were diagnosed with Secondary hypo. Do you have your blood test results from when you were diagnosed?

The endo thinks I’m over medicated. I do not believe I’m over medicated at all.

I expect he's only looking at the TSH. That's all most of them look at, they don't know any better.

I don’t have a range for the IGF-1 but the endo said it’s slightly raised so I’m having the OGTT.

I'm really confused now. What has a glucose tolerance test got to do with IGF 1? Or adrenal insufficiency come to that? It's a diabetes test. I think he's just trying all the tests he can think of in the hope that something will provide some answers. I don't get it at all.

He said the results are indicative of adrenal insufficiency.

Well, I can't see that, either, because your adrenals responded to stimulation. If you had adrenal insufficiency they wouldn't have responded. Seems more like they lack stimulation, which would be a pituitary problem.

I do hope you get referred to another endo, one that can untie the knots this endo has tied you up in!

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you very much! Yes, it’s all rather a mish mash!

In Feb 2022, the FT4 was out of range and the T3 was v low in the range. Thanks to this group telling me it was clear there was a conversion problem, I sourced T3 and started taking it. Eventually, I got it on the NHS.

I don’t know what secondary hypo is so I’ll look it up. So I’m guessing not!

My initial results were

TSH 3.14 (I think the range was 3.0-5.5)

FT4 was around 11

I have no idea what my T3 was.

How ridiculous to only look at the TSH. They are endocrinologists and all they do is the endocrine system. I don’t understand why they can’t know their subject.

Gosh the OGTT doesn’t make sense in relation to the IGF-1 or the AI.

I have all the symptoms of AI. I have lost about 6kg of weight, which I didn’t have to lose. I started at 55.9kg and I’m now at 49.6kg and I’m continuing to lose weight.

I failed the 30 minute SST but passed the 60 minute- but only just. You need to get over 450 at the 60 minute mark. Mine was 454. But you can pass an SST and still have AI. My ACTH is low but in range. It wouldn’t be PAI but SAI. I have a strong inhaler for my asthma and I have taken a lot of oral steroids because of it.

I don’t know much at all about pernicious anemia - despite just looking it up. How do you test for it?

What do you think of the vitamin D? The serum folate seems low in the range, is that okay?

I’ll call and see if they have registered me. Not much in the NHS moves quickly!

Thank you very much again.

greygoose profile image
greygoose in reply to AppleOrchard

I don’t know what secondary hypo is so I’ll look it up. So I’m guessing not!

Secondary Hypo is when the problem comes from the pituitary rather than the thyroid itself - i.e. a healthy thyroid but a sick pituitary.

When the problem comes from the thyroid itself, such as in Hashi's - do you have Hashi's? - it is called Primary Hypo.

And, then there is Tertiary Hypo, when the problem come from the Hypothalamus. But I've never heard of anyone being diagnosed specifically with that. It would probably be called Central Hypo because the cause cannot be defined - testing is difficult.

So, with Primary hypo, you would have high TSH, and low FT4/3.

With Central Hypo - i.e. Secondary and Tertiary hypo - you would have low TSH and low FT4/3. So, if we look at your results from diagnosis:

TSH 3.14 (I think the range was 3.0-5.5)

FT4 was around 11

The TSH isn't very high. Unusual to get a diagnosis with such a low TSH. BUT, that FT4 looks as if it might be under-range - it would be on some ranges. So, perhaps that was what got you the diagnosis, and that looks very much like Central Hypo - probably Secondary Hypo - i.e. faulty pituitary.

So, if your pituitary was unable to produce enough TSH, it was probably unable to produce enough of the other hormones. And, your cortisol was low, so, your pituitary probably wasn't making enough ATCH either - because there wouldn't seem to be anything wrong with your adrenals themselves because they responded to stimulation.

However, the problem with the SST test is that doctors don't really seem to know why they're doing it. As I see it, the results showed a pituitary problem, not an adrenal problem.

HGH is another pituitary hormone, so it's usual to test for that when investigating the pituitary. So, maybe your endo does know what he's doing, he just didn't explain it very well! However, I still can't see the point nor the relevance of the OGTT test in all that.

How ridiculous to only look at the TSH. They are endocrinologists and all they do is the endocrine system.

Yes, it is rediculous but in med school they are taught that the TSH tells them 'all they need to know'. It doesn't. That is assuming that everyone has a perfect, fully-funtional pituitary. Which they don't.

But, don't run away with the idea that endos know all about the whole endocrine system because that is far from the truth. The majority of them are diabetes specialist and know next to nothing about the other glands and hormones. They do not deal with the whole endocrine system by any means.

I have all the symptoms of AI. I have lost about 6kg of weight, which I didn’t have to lose.

Weight-loss is not necessarily a symptom of AI. It can also be a symptom of hypo. So, if you're under-medication it could be due to that. Do you crave salt?

I failed the 30 minute SST but passed the 60 minute- but only just. You need to get over 450 at the 60 minute mark. Mine was 454. But you can pass an SST and still have AI. My ACTH is low but in range.

SST is not a fail or pass kind of test. And it shouldn't be looked at like that. It's a 'let's find out what's causing the problem' kind of test. Is cortisol low because of an adrenal problem or a pituitary problem. If your ACTH is low in-range then it's more likely to be a pituitary problem. But, whatever the cause you still end up with low cortisol, which they should be treating - probably with HydroCortisone.

I don’t know much at all about pernicious anemia - despite just looking it up. How do you test for it?

There are blood tests your doctor can order, if he's of a mind. PA is an autoimmune disease where the body cannot store B12. Having a low B12 does not automatically mean you have it. Low B12 could be due to diet or just the hypo. But you need to know. If it's due to diet, etc. you can take sublingual supplements for it. But if it's PA, and your body can't stock that B12, then you need to have regular B12 injections for life. B12 deficiency can kill you, it's a very important vitamin. And, yet... doctors know nothing about it!

Difficult to say anything about the vit D because there's no range. But, the folate is low-ish. So, what you need for that is a good B complex with at least 400 mcg methylfolate. Thorne Basic B is a good one, or Igennus B complex. BUT don't start it until you've had your test for Pernicious Anemia because it will skew the results. :)

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you so much for your detailed reply. I really appreciate your time explaining.

At the time I was diagnosed, when I saw Dr Toft for the first time, other tests were done. Dr Toft was very clear that I didn’t have Hashimoto. So that would mean the problem is with the pituitary, as you said. And indeed, it would mean that perhaps it doesn’t produce other hormones as it should.

I didn’t know that about the TSH - but obviously Dr Toft did. He originally said I didn’t have UAT because of my results. He told me to come off the medication. I did and a week later I collapsed. It took months to recover. He sent me to have ann immediate blood test. And even then my TSH was only around 6.5. My FT4 was about 6.

That’s exactly it re the SST - not only are they clueless about why they might be doing it, they are clueless about interpreting the results. You can pass a SST but have SAI because the problem is with the pituitary rather than the adrenals. I have spent the last few months researching AI. You can even pass the SST with PAI. The salt craving comes with PAI. I do crave ready salted crisps and salted chips! And I put far more salt on than I used to but it could be a coincidence because I don’t have PAI.

I have seen that most are diabetes. That must be easier than UAT or AI! There is a saying that a vet could treat a human, but a doctor could not treat an animal. I think the training needs to change and be updated. But it won’t because it would have huge cost implications for treatment. It’s all about cost cutting and saving money.

I don’t think I’m under medicated - I have just had a reduction. Weight loss is a symptom of AI but not everyone has it. It’s also a symptom of diabetes. The weight loss has been fairly rapid and I’m still eating - although I don’t have much appetite for eating.

I have had low cortisol since Feb 2023. I wasn’t told that it was being taken and I was not told the result. It was lower than it should be then - especially since I was on HRT and took my inhaler before the test. There is a reason why cortisol is low, and that’s what needs to be found out. I’m sure it is pituitary related because of the ACTH.

I will wait to see the new endo re the B12. My GP is unlikely to do anything because it’s in range. As soon as something is in range, even if it’s only just, that’s it! You can forget about anything else being done.

I had no idea that B12 is as important as it is. I wish I had more time to research all these things at the same time.

I’ll see if I can find out the range of the D. The endo has an amazing secretary. If only he was as good at his job as she is at hers.

I’m holding off taking anything new until all the investigations are over. I don’t want anything to interfere with anything else.

Thank you so much again.

greygoose profile image
greygoose in reply to AppleOrchard

At the time I was diagnosed, when I saw Dr Toft for the first time, other tests were done. Dr Toft was very clear that I didn’t have Hashimoto. So that would mean the problem is with the pituitary, as you said.

Well, there are plenty of other causes of hypo, but you can tell it's the pituitary/hypothalamus by the low TSH with low Frees. Dr Toft was old school, and whilst I don't agree with everything he says, he did know his basics - which is more than modern doctors do!

I do crave ready salted crisps and salted chips! And I put far more salt on than I used to but it could be a coincidence because I don’t have PAI.

With most adrenal problems/low cortisol one has salt cravings. The adrenals need a lot of salt!

I have seen that most are diabetes. That must be easier than UAT or AI!

I don't know how much easier it is, because I know little about diabetes, but they say it's 'sexier', if you can believe that!

I think the training needs to change and be updated. But it won’t because it would have huge cost implications for treatment. It’s all about cost cutting and saving money.

It is indeed, but also they would have to admit they've been totally wrong all these years, and doctors aren't very good at that!

I don’t think I’m under medicated - I have just had a reduction. Weight loss is a symptom of AI but not everyone has it. It’s also a symptom of diabetes.

You're not exactly under-medicated but the balance is all wrong because you are a poor converter. On your last blood test your results were:

FT3: 5.7 pmol/l (Range 3.1 - 6.8) 70.27%

FT4: 21.3 pmol/l (Range 12 - 22) 93.00%

Percentage-wise, the gap between the FT4 and FT3 is much too wide. The FT3 should be just slightly lower than the FT4 if you convert well. And such a high FT4 is not good long-term, it can put you at risk of other problems, like heart disease and cancer.

So, was this test before the reduction in levo? Or after? Be interesting to see the results. The FT3 could either drop or rise. But one thing is certain, you don't want an increase in levo! But maybe a little T3 added to the levo? Time will tell.

There is a reason why cortisol is low, and that’s what needs to be found out. I’m sure it is pituitary related because of the ACTH.

I'm sure it is. And they've actually proved that but they don't know they have! 🤣 But there's not much anyone can do about a pituitary problem except replace the missing hormones. So, for the adrenals, that usually means HydroCortisone.

And, if you can find a doctor capable of testing HGH, AND of understanding the results, there are HGH injections you could have - although they are horrendously expensive! So difficult to get prescribed for an adult. Most doctors don't believe it serves any useful purpose for adults, but oh boy! it does!

I will wait to see the new endo re the B12. My GP is unlikely to do anything because it’s in range. As soon as something is in range, even if it’s only just, that’s it! You can forget about anything else being done.

Yes, most doctors are like that because they don't understand ranges. They are not taught in med school how to interpret blood test results, believe it or not. I would have thought that was a number 1 essential, but that's just me...

I’m holding off taking anything new until all the investigations are over. I don’t want anything to interfere with anything else.

OK, but don't hold off too long. Permenant neurological damage can be done if low B12 goes on too long.

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you once again!

I think it’s interesting that it’s my pituitary that causes the hypo. I didn’t know that. And all the more so because I remember Dr T testing my adrenals at the time. But I didn’t have AI then. That’s 20 years ago.

There's no way any doctor would admit to being wrong, let alone the whole system and all the training.

The ‘craving’ is also interesting. It reminds me of being pregnant. My craving was chips!! I put on so much weight, as you can imagine. At times, I dream of salted chips and crisps!! On the last test my sodium was okay but the one before it was slightly under range.

I’m learning a lot from you - thank you. Someone else on here suggested that I needed a reduction of T4 (down to 75mcg) and a slight increase of T3. The test was done before the reduction and prompted it. I was the one who suggested reducing it as he was going to leave it. My next step was to suggest an increase in T3 but one thing at a time. It’s hard because he doesn’t test T3. I’ll have to ask for it and no guarantee he will do it, What would you say my T3 should be? I’m currently on 10mcg.

I have an appointment with Dr Zachariah so I have my fingers crossed that he can do all aspects of AI and UAT.

I would agree - interpreting results should be taught, and firmly understood. It’s really very basic and totally essential.

My appointment is early July so less than a month. I’m going private and hope he can go NHS after that as I can only do one appointment privately!!

greygoose profile image
greygoose in reply to AppleOrchard

I think it’s interesting that it’s my pituitary that causes the hypo. I didn’t know that.

If the pituitary cannot, for whatever reason, produce enough TSH to stimulate the thyroid, then the thyroid cannot produce thyroid hormones. It aboslutely needs the TSH to be functional.

I remember Dr T testing my adrenals at the time.

Adrenals should always be tested at diagnosis because when the thyroid is failing, and cannot produce enough thyroid hormone to keep you well, the adrenals take up the slack by making extra cortisol. Which is why hypothyroidism often goes unnoticed for a long time. But, the adrenals cannot continue to do that indefinitely. They become fatigued - although very few doctors actually believ in adrenal fatigue - and the production of cortisol drops below optimal. With many people, this should be addressed before starting on thyroid hormone replacement.

The ‘craving’ is also interesting. It reminds me of being pregnant.

The three times I was pregnant I tended to go off things, rather than crave them. The first time, just the smell of bread made me vomit. But, I craved mashed potatoes, custard creams and grapefruit! 🤣 Much the same with the second one, although I did want hard boiled sweets a lot. With the third one all I could eat was oranges. And I ate them by the crate-load! Lost a lot of weight and got told every at every doctor appointment for not looking after myself properly! Like I had a choice!

What would you say my T3 should be? I’m currently on 10mcg.

I wouldn't. Once the FT3 is over mid-range - below is too low - it's up to the individual to find out what they need by trial and error - or it would be if doctors would allow it! Try and increase and see how you feel.

Good luck with your new endo! Let us know how you get on. :)

AppleOrchard profile image
AppleOrchard in reply to greygoose

You have written everything in such a clear way. I wonder if my cortisol has become lower and lower over the years. It was Covid that really triggered the symptoms. I’d had some before but it was only one or two.

Yes, doctors don’t believe in AF. A lot of people don’t, I’d say. It’s a tricky one.

It’s funny the things pregnancy hormones do! There’s always a reason for disliking or liking something. Mashed potatoes really isn’t too bad! I couldn’t stand the smell of bread maker bread! It resulted in me getting rid of the machine. Spinach was another, and the fridge!

I wish doctors would allow their patients to be more involved in their treatment. We know our own bodies and we know how we feel.

Once I have had my appointment, I’ll come back and let you know.

Thank you very much again for all your help. I have learned a lot!

greygoose profile image
greygoose in reply to AppleOrchard

You're very welcome. :)

Yes, covid did a number on many of us. I haven't been the same since I had it in October 2022. It was a terrible thing - not just at the time but long time after.

I was lucky that I had a doctor for a while that did believe in AF. Because he had it himself! And he was the one that diagnosed me with it and put me on HydroCortisol for a while. But, my cortisol was a lot lower than yours. Even so, after a couple of years I was able to wean myself off it. But, of course, I didn't/don't have a pituitary problem. My HGH was also low and he put me on daily HGH injections for a while. Unfortunately, he's retired now, so all that has come to an end. I self-treat, now.

I wish doctors would allow their patients to be more involved in their treatment. We know our own bodies and we know how we feel.

That is exactly what they should do, according to NICE. But although doctors love to go on and on about their hands being tied, I don't think many of them have actually read the NICE guidelines - which, in any case, are only guidelines, not rules. Or else they just pick out the bits they like and ignore the rest! :)

AppleOrchard profile image
AppleOrchard in reply to greygoose

I’m sorry Covid has had such a bad effect on you. It’s a terrible illness and far from the cold that lots of people said.

I have had Covid four times now and every time, apart from the first (I got antivirals), I have been left with something lasting. And on the last occasion, I ended up in hospital for four days.

You were indeed very lucky. It’s good you got treatment and that you managed to get it sorted. It’s not a pleasant thing. What a pity he’s retired.

As you say, most doctors don’t read the guidelines. I think they should be more than guidelines for that very reason. Most don’t know the guidelines and don’t treat their patients accordingly. They should be rules and the doctors should be made to follow them. Right now, they are just a pointless pen pushing exercise. It’s like writing a policy and then completely ignoring it. I guess that’s done all the time too!

Thank you very much again. I’d have replied today but I had a vomiting child at home. It’s been a long day!

greygoose profile image
greygoose in reply to AppleOrchard

Oh dear! Sorry to hear about the vomiting child! I've had a few of those myself, and it's not nice! Hope s/he gets over it soon. x

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you! She’s off school today. Her tummy muscles hurt and she’s now full of the cold x

greygoose profile image
greygoose in reply to AppleOrchard

Oh dear, poor mite. Sending lots of hugs! 😘

AppleOrchard profile image
AppleOrchard in reply to greygoose

Thank you x

greygoose profile image
greygoose in reply to AppleOrchard

You're welcome. :)

nilly-batu profile image
nilly-batu

sorry late reply, im still not gr8 on numbers. So not the greatest to ask: i am on 75mcg thyroxine 10gr lio: keeping vitd up to scratch & b12. Feeling well & gd balance is essential. Hope you have had some gd suggestions.

AppleOrchard profile image
AppleOrchard in reply to nilly-batu

Thank you - I have had a lot of great help.

You may also like...

Blood test results help

exactly). Thyroid blood test results from this year (2018): 01/18 FT4: 13.3 pmol/L (12.0-22.0) FT3:...

Advice on Blood Tests + Levo dose

nmol/L (Range: 50 - 175) Thyroid Hormones TSH X 0.07 mIU/L (Range: 0.27 - 4.2) Free T3 4.95 pmol/L...

New blood test results

got my blood results back today and would really appreciate any comments! I’m on 100mcg...

Latest blood test results

before the tests. I took a monitor my health test just after 8 am and followed it up with a test at...

Re Thyroid Blood Tests

28.3 pmol/L dose to 75mcg as planned Serum TSH Reduce 0.12 mu/L dose to 75mcg as...