Possible misdiagnosis of type 2 diabetes

Brendan_M · Mar 19, 2023

I was diagnosed with type 2 diabetes in the spring of 2019 at the age of 31. I went to the doctor for unexplained weight loss of 15 lbs over a few months. Blood work came back with an A1C of 7.8%. Because of my lack of risk factors (healthy weight, active lifestyle) and history of Celiac disease, my GP suspected type 1. I was referred to an endocrinologist who was very adamant that it was type 2 because my blood glucose wasn't that bad and I was too old for type 1. I asked for a c-peptide and GAD test but she insisted that was unnecessary and with the wait times to see a new endocrinologist i didn't have many options. So I was put on Janumet 50/1000mg (Sitagliptin/Metformin) twice a day. I some how got my insurance to cover the freestyle libre even though i wasn't taking insulin. By the summer my A1C was down to 5.2%. I used the freestyle libre for about a year and half until my insurance changed and the new one wouldn't cover them. I kept doing finger pricks for a while but like clockwork my bg was always between 4-7 mmol/l. I got complacent and just kind of carried on with the assumption that all was still good. Fast forward to the end of January of this year, I did my regular blood work and my random bg was 21.1 mmol/l and A1C was 12%. My GP put me on Lantus 12u a day. Took a couple of weeks but my bg got back to a more manageable level, still not great though. I was referred to a diabetic clinic at the hospital, as my endocrinologist had retired. They sent me for labs including C-peptide and GAD and started me on a sliding scale of fast acting insulin. I just got my C-peptide results back (536 pmol/l)(I wasn't fasting), my blood glucose at the time of the test was 13 mmol/l. I am still waiting for the results of the GAD test but my c-peptide levels were higher than I expected them to be. My doctor hasn't called to go over the results yet, as I'm assuming they are waiting until they have all the tests back. Would those c-peptide levels be consistent with someone with LADA who still has decent beta cell function? Or does that level rule out LADA? If all of these tests come back negative they plan to send me for genetic testing for MODY

Antje77 · Mar 19, 2023

Brendan_M said:
Would those c-peptide levels be consistent with someone with LADA who still has decent beta cell function?

Very well possible, yes.

Another thing to note is that there are more antibodies than the GAD ones, so if that test comes out negative it does not rule out T1.

Brendan_M said:
endocrinologist who was very adamant that it was type 2 because my blood glucose wasn't that bad and I was too old for type 1.

Glad he retired, if I remember correctly some 50% of T1's develop it when over 30.

Let us know what happens, glad it's been looked into now!

Daibell · Mar 19, 2023

Hi. Be aware that C-Peptide tests can be unreliable. I had a plasma one done privately and it showed very low insulin. Later I had a urine one done in the NHS and it showed higher insulin. With the urine test, they use a ratio of peptide and creatine and this can be unreliable as creatine varies a lot day to day. The blood plasma test needs the sample to be kept very cold which is not easy. Either way expect varied test results. If GAD comes out negative it means very little and rely on the C-Peptide. My NHS consultant treats me a T1 despite my C-peptide being slightly above the T1 reference level. He looks at my weight and BS levels on my Libre together with my insulin needs.

Brendan_M · Mar 19, 2023

Antje77 said:
Very well possible, yes.

Another thing to note is that there are more antibodies than the GAD ones, so if that test comes out negative it does not rule out T1.

Glad he retired, if I remember correctly some 50% of T1's develop it when over 30.

Let us know what happens, glad it's been looked into now!

Thanks for the reply. I had also read that around 50% of T1’s develop over 30 so was very surprised when she was so dismissive. I will have to look into tests for the other antibodies if the GAD comes back negative.

Brendan_M · Mar 19, 2023

Daibell said:
Hi. Be aware that C-Peptide tests can be unreliable. I had a plasma one done privately and it showed very low insulin. Later I had a urine one done in the NHS and it showed higher insulin. With the urine test, they use a ratio of peptide and creatine and this can be unreliable as creatine varies a lot day to day. The blood plasma test needs the sample to be kept very cold which is not easy. Either way expect varied test results. If GAD comes out negative it means very little and rely on the C-Peptide. My NHS consultant treats me a T1 despite my C-peptide being slightly above the T1 reference level. He looks at my weight and BS levels on my Libre together with my insulin needs.

Thanks, I had no idea C-peptide tests could be unreliable. I figured they basically used that and antibody tests for diagnosis. From what I’ve read it seems that some beta cell function can be preserved for years with LADA so makes sense that they are just watching your weight and BS levels. Because I have Celiac disease I was already following a pretty low carb diet. Once I was diagnosed with diabetes I went keto. Worked very well for a few years but clearly something has changed. After a protein shake (no carb protein powder, almond milk and a little natural unsweetened peanut butter) for breakfast, my blood sugar can easily get up into the 15’s. So clearly something has changed.

kogert · Mar 21, 2023

Brendan_M said:
I was diagnosed with type 2 diabetes in the spring of 2019 at the age of 31. I went to the doctor for unexplained weight loss of 15 lbs over a few months. Blood work came back with an A1C of 7.8%. Because of my lack of risk factors (healthy weight, active lifestyle) and history of Celiac disease, my GP suspected type 1. I was referred to an endocrinologist who was very adamant that it was type 2 because my blood glucose wasn't that bad and I was too old for type 1. I asked for a c-peptide and GAD test but she insisted that was unnecessary and with the wait times to see a new endocrinologist i didn't have many options. So I was put on Janumet 50/1000mg (Sitagliptin/Metformin) twice a day. I some how got my insurance to cover the freestyle libre even though i wasn't taking insulin. By the summer my A1C was down to 5.2%. I used the freestyle libre for about a year and half until my insurance changed and the new one wouldn't cover them. I kept doing finger pricks for a while but like clockwork my bg was always between 4-7 mmol/l. I got complacent and just kind of carried on with the assumption that all was still good. Fast forward to the end of January of this year, I did my regular blood work and my random bg was 21.1 mmol/l and A1C was 12%. My GP put me on Lantus 12u a day. Took a couple of weeks but my bg got back to a more manageable level, still not great though. I was referred to a diabetic clinic at the hospital, as my endocrinologist had retired. They sent me for labs including C-peptide and GAD and started me on a sliding scale of fast acting insulin. I just got my C-peptide results back (536 pmol/l)(I wasn't fasting), my blood glucose at the time of the test was 13 mmol/l. I am still waiting for the results of the GAD test but my c-peptide levels were higher than I expected them to be. My doctor hasn't called to go over the results yet, as I'm assuming they are waiting until they have all the tests back. Would those c-peptide levels be consistent with someone with LADA who still has decent beta cell function? Or does that level rule out LADA? If all of these tests come back negative they plan to send me for genetic testing for MODY

Hi, I was diagnosed with type 2 diabetes at the age of 33 after feeling very poorly and unexplained weight loss (I was overweight to begin with). I was put onto a cocktail of oral medication, but nothing seemed to work, so after around 6 months I was put onto Insulin. I was never tested to determine if I was type 1 or type 2 as I was overweight and, as you commented on, I was not the right age for it to be type 1. Over the years, I have often receive questions about whether I am type 1 or type 2, but no further action was ever taken. Fast forward 18 years, during a review with a new doctor and diabetes team in January this year, further tests were carried out and it is now confirmed that I am type 1 not type 2 as originally diagnosed. My treatment has not changed, I still take insulin 5 times a day, but I feel attitudes towards me have. I now have a Libre, which is life changing, and I have been enrolled onto a DAFNE course. I know this does not answer your question, but I wanted to comment as we so often get 'categorised' into perfect little boxes that do not always fit! Good luck with the diagnosis!

Brendan_M · Mar 21, 2023

kogert said:
Hi, I was diagnosed with type 2 diabetes at the age of 33 after feeling very poorly and unexplained weight loss (I was overweight to begin with). I was put onto a cocktail of oral medication, but nothing seemed to work, so after around 6 months I was put onto Insulin. I was never tested to determine if I was type 1 or type 2 as I was overweight and, as you commented on, I was not the right age for it to be type 1. Over the years, I have often receive questions about whether I am type 1 or type 2, but no further action was ever taken. Fast forward 18 years, during a review with a new doctor and diabetes team in January this year, further tests were carried out and it is now confirmed that I am type 1 not type 2 as originally diagnosed. My treatment has not changed, I still take insulin 5 times a day, but I feel attitudes towards me have. I now have a Libre, which is life changing, and I have been enrolled onto a DAFNE course. I know this does not answer your question, but I wanted to comment as we so often get 'categorised' into perfect little boxes that do not always fit! Good luck with the diagnosis!

Thanks for sharing! Crazy it took the system that many years to give you a correct diagnosis. Like you said, knowing won't really change my treatment at this point. But it does open up some other treatment/monitoring options with insurance. It will also be nice to get a better idea what I can expect in terms of progression.

Brendan_M · Mar 23, 2023

Just got my GAD65 antibodies test results back:
64 iu/ml. Reference range was 0-5 iu/ml. Still waiting to hear from my endocrinologist, but I’m assuming that it’s likely type 1/LADA then. I think my beta cell function is declining pretty rapidly at this point. Having a very difficult time keeping my bg under 10 using the sliding scale dosing of fast acting they gave me, even on a low carb diet.

Mrs HJG · Mar 23, 2023

Hi @Brendan_M I was diagnosed T1/LADA at age 52, my GAD was 220 and therefore consistent with T1; after 12 months this reduced to 83, which my consultant says is probably due to my new low carb diet, exercise and routine which has reduced and kept my BG in non-diabetic range since 3 months in, and no need for insulin yet. My other anti-bodies were positive too.

There are those with antibodies who aren't diabetic, and people with T1 diabetes who are antibody negative, it is not as simple as most people would have you believe and skinny oldies get it too! Definitely looks like your doctor was one of the old school uneducated. Hopefully now you will get all the support a T1 needs.

Bashert · Jul 15, 2023

Brendan_M said:
I was diagnosed with type 2 diabetes in the spring of 2019 at the age of 31. I went to the doctor for unexplained weight loss of 15 lbs over a few months. Blood work came back with an A1C of 7.8%. Because of my lack of risk factors (healthy weight, active lifestyle) and history of Celiac disease, my GP suspected type 1. I was referred to an endocrinologist who was very adamant that it was type 2 because my blood glucose wasn't that bad and I was too old for type 1. I asked for a c-peptide and GAD test but she insisted that was unnecessary and with the wait times to see a new endocrinologist i didn't have many options. So I was put on Janumet 50/1000mg (Sitagliptin/Metformin) twice a day. I some how got my insurance to cover the freestyle libre even though i wasn't taking insulin. By the summer my A1C was down to 5.2%. I used the freestyle libre for about a year and half until my insurance changed and the new one wouldn't cover them. I kept doing finger pricks for a while but like clockwork my bg was always between 4-7 mmol/l. I got complacent and just kind of carried on with the assumption that all was still good. Fast forward to the end of January of this year, I did my regular blood work and my random bg was 21.1 mmol/l and A1C was 12%. My GP put me on Lantus 12u a day. Took a couple of weeks but my bg got back to a more manageable level, still not great though. I was referred to a diabetic clinic at the hospital, as my endocrinologist had retired. They sent me for labs including C-peptide and GAD and started me on a sliding scale of fast acting insulin. I just got my C-peptide results back (536 pmol/l)(I wasn't fasting), my blood glucose at the time of the test was 13 mmol/l. I am still waiting for the results of the GAD test but my c-peptide levels were higher than I expected them to be. My doctor hasn't called to go over the results yet, as I'm assuming they are waiting until they have all the tests back. Would those c-peptide levels be consistent with someone with LADA who still has decent beta cell function? Or does that level rule out LADA? If all of these tests come back negative they plan to send me for genetic testing for MODY

Sounding very similar to what im going through now,see the diabetes specialist team for the first time this week

searley · Jul 20, 2023

ive been through this.. cpeptide of less that 600 is low.. its at the top end of low.. typically T2's will have much higher cpeptide as they are over producing insulin to try and control BG

Also rapid weight loss is not typically associated with the T2.. however when tested i never had GAD antibodies..

my cpeptide was 636, and 12 months later it was 60

Mungobean · Jul 25, 2023

Brendan_M said:
Thanks for the reply. I had also read that around 50% of T1’s develop over 30 so was very surprised when she was so dismissive. I will have to look into tests for the other antibodies if the GAD comes back negative.

I developed T1 at 51 having previously been diagnosed with T2. I wasn’t concinced about the diagnosis and got
my GO to test for T1, It was only a week or two ago that someone very condescendingly informed me in a forum that ‘just because I was taking insulin it didn’t mean I was T1 and that T1 was only diagnosed in childhood! I was fuming

Possible misdiagnosis of type 2 diabetes

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Possible misdiagnosis of type 2 diabetes

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