Misdiagnosed as type 2 - how common is it?

I'm not sure how common it is.

Things that might suggest type 1 include:-
- on the younger end of the spectrum on diagnosis (although that's a pretty weak indicator, because I think something like 20% of type 1s are over 50 on diagnosis)
- very high blood sugar 30+ on diagnosis
- dka on diagnosis
- sudden, untried for dramatic weight loss (I.e. Losing 10% of your body weight while eating more than normal)

If any of those things sound familiar, it might be worth asking for cpeptide and GAD tests to see if you can determine type.

Hi
I also wondered about this for much the same reasons as well as having several autoimmune issues. I had a fasting c-peptide test that came back at twice the highest normal level. This pretty much guarantees that I am type 2 with hyperinsulinemia and very high insulin resistance. This is an easy and common test.

Where I am you get referred to a diabetic clinic to see an endocrinologist. The first thing they do is run diagnostic tests (the GAD test and c-peptide test as Catapillar has mentioned). The outcome of those tests tell them what type you have.

Over the years I've had these diagnostic tests run 3 times on me. One in 1998 on diagnosis which showed I produced sufficient insulin and had no antibodies, another one in 2005 which showed the same, and then the final one in 2010 which showed no antibodies but that I hardly produce insulin. So I'm now dealing with not just insulin resistance, but insulin deficiency. I am still type 2.

Hopefully you can get these tests done if you haven't had them done to find out what type you have. If you've not had these tests done then I can understand that you could easily be misdiagnosed as they can't tell what type you have just from the hbA1c test and glucose tolerance test alone.

Obviously from what I've mentioned above you can still be type 2 and have insulin deficiency. If that is the case you will need to be on insulin therapy. Insulin deficiency alone doesn't mean you're automatically type 1... you have to also have antibodies for type 1 as that is an auto-immune disease. But your docs should be checking this for you.

I wish you the best.

chalup said:

Hi
I also wondered about this for much the same reasons as well as having several autoimmune issues. I had a fasting c-peptide test that came back at twice the highest normal level. This pretty much guarantees that I am type 2 with hyperinsulinemia and very high insulin resistance. This is an easy and common test.

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Hi @chalup this isn't necessarily true. Before being diagnosed as T1 my GP did a c peptide test, which came back abomorally high. Later gad and another c peptide tests was done, showing that I was T1, gad was positive and c peptide was low. My endo concluded the initial c peptide showed my body trying to use as much insulin as I had left - working overtime, or perhaps a little resistance as does happen in LADA. So c peptide tests aren't conclusive at all

tpaz said:

Hi @chalup this isn't necessarily true. Before being diagnosed as T1 my GP did a c peptide test, which came back abomorally high. Later gad and another c peptide tests was done, showing that I was T1, gad was positive and c peptide was low. My endo concluded the initial c peptide showed my body trying to use as much insulin as I had left - working overtime, or perhaps a little resistance as does happen in LADA. So c peptide tests aren't conclusive at all

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Thank you, I had not heard this before. My doctor has put in a referral to an endo but I am still waiting for an appointment. I will ask for the GAD test when I do get in. I have been VLC for months and I still had a fasting of 8.3 and an A1c of 6.7. I am also only losing about 5 lbs a month despite being well under 2000 cal per day, sometimes under 1000. 10 years ago my numbers dropped into the 4's and the weight fell off. All within days of starting low carb. Should have never listened to "you are not diabetic anymore".

chalup said:

Thank you, I had not heard this before. My doctor has put in a referral to an endo but I am still waiting for an appointment. I will ask for the GAD test when I do get in. I have been VLC for months and I still had a fasting of 8.3 and an A1c of 6.7. I am also only losing about 5 lbs a month despite being well under 2000 cal per day, sometimes under 1000. 10 years ago my numbers dropped into the 4's and the weight fell off. All within days of starting low carb. Should have never listened to "you are not diabetic anymore".

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Everyone is different. A lot of people will say they lost a lot of weight prior to a T1 diagnosis and insulin puts the weight back on them. I had the exact opposite experience. Prior to diagnosis, I had put on a good deal of weight and my BG levels were out of control. Now being on insulin, the weight has steadily come off. I feel when my levels are under control, it's much easier for me to lose weight. There's a lot of mainstream information out there, but it doesn't apply to everyone personally, LCHF did not help me with weight. Adding hi fiber grains in a moderate amount (60-80g per day) has been part of my solution to losing weight. I also saw a huge increase in my lipids when on LCHF, that I'm still fighting to bring down. I know this site has a lot of advocates for LCHF, but it wasn't what worked for me and my body.

tpaz said:

Everyone is different. A lot of people will say they lost a lot of weight prior to a T1 diagnosis and insulin puts the weight back on them. I had the exact opposite experience. Prior to diagnosis, I had put on a good deal of weight and my BG levels were out of control. Now being on insulin, the weight has steadily come off. I feel when my levels are under control, it's much easier for me to lose weight. There's a lot of mainstream information out there, but it doesn't apply to everyone personally, LCHF did not help me with weight. Adding hi fiber grains in a moderate amount (60-80g per day) has been part of my solution to losing weight. I also saw a huge increase in my lipids when on LCHF, that I'm still fighting to bring down. I know this site has a lot of advocates for LCHF, but it wasn't what worked for me and my body.

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I had the same problem with lipids when I was on that diet. That's why I chose to come off it as I can't risk keeping it high as heart disease runs in my family and so does high cholesterol levels. I know it works well for a lot that try it... but for some like myself it's just not worth it.

@andyfh and @chalup I hope you find answers and a correct diagnosis from your respective diabetes teams - sending every good wish in that respect!

Thanks @tpaz and @Mep for insights into your LCHF experiences - I'm currently trying to modify the HF aspect of my own LCHF approach to NormF after a big hike in my total cholesterol results last week.

The LC aspect is absolutely fab for my control, and my weight is steady (and just where I want it, fortunately) but I'm now not going out of my way to use added fat in my cooking and in my snack choices, for the sake of my cholesterol numbers.

Hi. Normally having a lot of excess weight would imply T2 and make T1 unlikely. As @catapillar says, loss of weight unexpectedly (and also not being much if any overweight to start with) are T1 indicators. That was my situation. I think @tpaz experience may be an exception rather than the rule as the c-peptide test is a key test for insulin levels but I'm sure it sometimes goes wrong and the actual results can only be interpreted as 'too low' or 'too high'. The unexpected loss of weight is due to the body burning fat or protein instead of carbs due to lack of insulin and a c-peptide test should show a low reading as mine did. It is of course possible to have insulin resistance and lower c-peptide due to islet cell destruction thru excess blood sugar i.e. a mix of conditions. I suspect if you can reduce the remaining excess weight (well done so far) and hence insulin resistance you may find your blood sugar comes into the normal range. LADAs may often have blood sugars in the 20s before insulin starts despite taking all the tablets. If your sugars are regularly in the teens you might want to ask for a c-peptide test. Ref how common is Late onset T1 I would suggest that a good proportion of 'T2s' who are not overweight at diagnosis ( around 15% - 20%) may actually be T1 but I can only guess?

also bg of 8.5 is not indicitive of T1 - it would be more like 38.5 lol

and speaking of cholesterol.... I'm in the %$#@ again with it as just found out today after posting above that it is high again. Total was 6.8 but the LDL was 4.8 (went up which isn't good) with HDL of 5.5 (went down which isn't good) I'm not impressed. I was expecting a bad result though as my diet hasn't been exactly healthy since I've eliminated a lot of healthy things I used to eat from my diet thanks to trying to avoid more pain my bladder condition and IBS (yep both are sensitive and react to food and drinks). I tell you what it is an absolute pain trying to eat for multiple conditions. I've been placed on a statin as of today... I'm fortunate I wasn't put on it sooner though. All the others in my family with high cholesterol have been on statins for years and I always managed to avoid it and I have the lowest cholesterol readings usually. But back in 2005 when they were wanting to put me on it I didn't qualify as I was always under the limit to get the drug subsidised. Since then the cholesterol total has dropped to 5.5 to qualify diabetics to get the drug subsidy here. I recall cardiologists lobbying the govt so it must've worked partly in their favour. But for me right now I need to reassess my diet again which I'm constantly doing anyhow. Hopefully the med will help too. I've mixed feelings on it.... but I just have to keep at it.

andyfh said:

Hi all.

I am newly diagnosed type 2 (couple of months) and wondered how common is it for people to be initially diagnosed as type 2, only to find out some time later that they were type 1 all along?

Since being diagnosed I have cut my carbs to the bone and stuck to the LCHF diet religiously. I still have a couple of stone to lose, but I've lost 22lbs since d day, going from 16st 6 to 14st 10. (I'm a 55 year old, 6'1" male).

Despite taking 3 x 500 metformin per day and avoiding carbs & sugar like a zealot, I can't seem to get my BG readings below 8.5 at any time throughout the day and my feet are stinging constantly.

It may be that I need to up my excercise or that my meter (codefree) is on the blink, but having seen others mention misdiagnosis in a few threads, I thought I would ask about its rarity or otherwise.

In advance of the inevitable question, I haven't the foggiest what my blood results were, but will be requesting them next week as I need to produce them at the X-pert course I have been asked to attend.

Thanks for reading.

Andy

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It does take a little while to get your readings down, you are probably due another HbA1c which will give you a better overall reading. Due to your age and weight it is more likely that you are Type 2 but ask for a follow up appointment to get more information. You are on the right track though, well done for your weight loss!

My starting A1c on May 5 10.4%
not sure what fast was but very high, low 20's
Am also on metformin 3 X 500mg per day
Also very low carb religiously
Also lost only 20 lbs
Do we know each other? twins maybe ? lol

Engineer88 said:

also bg of 8.5 is not indicitive of T1 - it would be more like 38.5 lol

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Again, it depends. LADA's can float around and maybe even never hit the 30's until their pancreas completely stops producing insulin. I was in the 7-10 range regularly on Metformin, don't think I've ever been over 20, although can't say that for sure. My AIC had me averaging 9 or 10 mmol, when I had a T1/LADA diagnosis.

tpaz said:

Again, it depends. LADA's can float around and maybe even never hit the 30's until their pancreas completely stops producing insulin. I was in the 7-10 range regularly on Metformin, don't think I've ever been over 20, although can't say that for sure. My AIC had me averaging 9 or 10 mmol, when I had a T1/LADA diagnosis.

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Yeh my sugar level only really jumped by about 3-4 mmol higher than usual when I had insulin deficiency. But then at the time I was very strict with diet and exercise... was doing 2 hours every day. I got real sick and had to stop. But I think without all the exercise and being tight with my diet I may have been a lot higher. I don't know exactly what my c-peptide result was in numbers but my endo said I hardly produce insulin so I'm assuming it was a low number... all I saw was it was red which I know isn't good. Also remember reading somewhere that an average of 1 in 3 T1's still produce some of their own insulin... especially if they were diagnosed as adults. So not all T1's have absolutely no insulin whatsoever being produced. My endo warned me as a T2 I can also have absolutely no insulin being produced in future... he said he sees that all the time in people who have been T2 for a while. I'm already at the deficient stage so I guess that makes sense. I'd imagine LADA is similar in that they still produce some insulin and then they may not in future. But yeh your sugar may be real high if you have no insulin at all being produced for sure. So to say T1's would have sky high sugar would not necessarily be true, I agree.

Mep said:

Yeh my sugar level only really jumped by about 3-4 mmol higher than usual when I had insulin deficiency. But then at the time I was very strict with diet and exercise... was doing 2 hours every day. I got real sick and had to stop. But I think without all the exercise and being tight with my diet I may have been a lot higher. I don't know exactly what my c-peptide result was in numbers but my endo said I hardly produce insulin so I'm assuming it was a low number... all I saw was it was red which I know isn't good. Also remember reading somewhere that an average of 1 in 3 T1's still produce some of their own insulin... especially if they were diagnosed as adults. So not all T1's have absolutely no insulin whatsoever being produced. My endo warned me as a T2 I can also have absolutely no insulin being produced in future... he said he sees that all the time in people who have been T2 for a while. I'm already at the deficient stage so I guess that makes sense. I'd imagine LADA is similar in that they still produce some insulin and then they may not in future. But yeh your sugar may be real high if you have no insulin at all being produced for sure. So to say T1's would have sky high sugar would not necessarily be true, I agree.

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Right, so LADA and T1 are exactly the same thing with one small difference - the length of honeymoon or not even having a honeymoon. T1s are usually (not always, but usually) diagnosed as kids or young adults. They don't really have a honeymoon period. And need insulin right away. Kids immune systems aren't great and when antibodies start attacking, their bodies just don't have the power to fight back.

LADA is just a slower progression of the same disease. But because we're older and have built up various viruses thoroughout our lives, our bodies will try to fight the pancreas antibodies, causing the honeymoon period. It's just your body using as much as you've got left and fighting against those antibodies. So many LADA patients are misdiagnosed as T2, and given Metformin. Some of us see an actual improvement because Metformin is helping us to be super receiving to the the little insulin we are producing. This can last days, weeks or months. Then there comes a time when neither diet, exercise or pills will help. We need insulin.

tpaz said:

Right, so LADA and T1 are exactly the same thing with one small difference - the length of honeymoon or not even having a honeymoon. T1s are usually (not always, but usually) diagnosed as kids or young adults. They don't really have a honeymoon period. And need insulin right away. Kids immune systems aren't great and when antibodies start attacking, their bodies just don't have the power to fight back.

LADA is just a slower progression of the same disease. But because we're older and have built up various viruses thoroughout our lives, our bodies will try to fight the pancreas antibodies, causing the honeymoon period. It's just your body using as much as you've got left and fighting against those antibodies. So many LADA patients are misdiagnosed as T2, and given Metformin. Some of us see an actual improvement because Metformin is helping us to be super receiving to the the little insulin we are producing. This can last days, weeks or months. Then there comes a time when neither diet, exercise or pills will help. We need insulin.

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Oh yes definitely you need insulin. I need insulin as well. Anyone with insulin deficiency or no insulin needs the exogenous insulin. If you have sufficient insulin that's when you can probably come off it in future. I was never put on insulin until they found out I hardly produce it, but I do know some T2's are put on it to get quick control but they aren't deficient in it. I do get asked if I'm LADA, but I'm not. I have never had any positive GAD test result.

andyfh said:

Anywho, I have just hot footed it back from my GP and having paid over my £3 have now got my hands on a copy of the HbA1c test results

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You had to pay £3 to get a paper copy of your HbA1C? WHAT??