Hi, My endo recently had me get a C peptide test b/c she supsects I may actually have LADA. The test came back with high levels and she is ordering an antibody test. I thought hight C peptide meant type 2 and low was type 1. She said that the test was unequivocal. Does anyone know of why a type 1 (LADA) would have hight C peptide levels?

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While high c-peptide levels are usually indicative of insulin resistance, it largely depends on what your BG level was at the time the test was taken. Do you know what your BG was at that time and how high was the c-peptide? If your BG was low-normal, a high c-peptide is a pretty good indication of T2. But if your BG was high, it wouldn't be out of the ordinary for your c-peptide to also be high (but still within the "normal" range). As LADA sometimes includes a long honeymoon period, it's likely that even if were are LADA, you'd still be making some insulin for a while.

Are you on oral meds? If so, have they had any impact on your BG? If you are insulin resistant (T2), meds like metformin will help lower your BG. But, if you're LADA, they won't really help (since insulin resistance is not the problem). Some meds (sulfonylureas) actually increase insulin production, so they can help LADAs during the extended honeymoon period. However, many endos are leaning towards putting LADAs straight on insulin to preserve any remaining beta cell function.

Thanks for the info. I don't have my C peptide value but I will get it. My BG was 155 according to the lab and 181 according to my meter at the time of the test, however it was much higher when I woke that morning (289). I was diagnosed in Dec. 2005 and the metformin worked very well at first. Only this year has it been more difficult to control, but I also eat very poorly. When I go very low carb I come down into almost normal range (120s on waking and 145-170 postprandial). I will tolerate increased carbs for a short while from that point but if I begin to make it a regular habit I stay VERY high for weeks even with a decrease in carbs. My endo just started me on 20 units of Levimir and a base of 6 novolog plus 1 unit for every 30 above 100 for correction at mealtime. I haven't seen any results from that yet...likely the wrong dose??? Based on this do you have any additional thoughts??

A few things pop out at me right off. 1st, your morning fasting was 289 mg/dl, but lowered on it's own (or with the help of metformin) before your blood was drawn. This means that your pancreas is still making insulin (which we knew from your elevated c-peptide). But, to know what that means will really depend on how high your c-peptide was.

Next, with a venous BG of 155, you would expect an elevated c-peptide (given that your body was still making insulin - mine's not). I believe the "normal" range for c-peptide is 0.8 ng/mL - 3.1 ng/mL. So, if you're within that range, and combined with your elevated fasting BG, I would understand why your endo wanted an antibody test. BUT, a higher than the high end of normal reading would be a very strong indicator of insulin resistance (T2).

A starting dose of 20U of Levimar is fairly conservative. What did you mean by "a base of 6 novolog?" Are you taking 1U of Novolog for every 6 carbs? Are you carb counting at all? Your Novolog correction dose (1U for every 30 mg/dl over 100 mg/dl) is fairly aggressive for a T1, so if it's having little-to-no impact, I would interpret that to mean insulin resistance. Did your endo give you any titrating instructions? How often are you testing?

When will you get the antibody testing done? Is she checking for more than one type (GAD-65, IA-2, ICA, etc.). It is my understanding that GAD-65 is the most common in LADA, but any could be present.

I guess the bottom line is that information is critical in figuring this out. Also, please note that I'm not a doctor, CDE, or any other "professional." Just someone who did tons of research in getting my own diagnosis straightened out (you can read about it here).
My "base" means I am to take 6U at mealtime along with 1 unit per 30 over 100) so if my BG before lunch is 130 I would take 7U for example. I will also see what Ab testing she is ordering...good point. Based on what you are saying it would make sense if I was LADA still making some insulin and also with insulin resistance...agreed? I guess the blood tests will give me answers soon enough. I have always been scared of taking insulin but the more I read the more I realize whether I am type 1 or 2 it may be a very good treatment option. Also to answer you...I am NOT carb counting at this point but she told me that she would have me start doing that very soon. I have never seen a specialist until recently. I was diagnosed as type 2 put on orals and not had any other education or treatment. Since I am a healthcare provider I guess it is assumed that I don't need much in the way of education, but that is not necessarily true. I appreciate your insight greatly!!

Hmmm, so, you're taking 6U of Novolog regardless of what you eat? If you decide to start low-carbing again, make sure you test your BG frequently. Lows sucks!

I just thought of another question: have you ever tested for ketones? With a BG of 280 mg/dl or higher, it is possible that you'd spill ketones (if you're a T1). I don't think T2s spill ketones, except in rare cases. Also, have you had any unexplained weight loss? These are common T1 signs.

But, to answer your question, yes, it sounds like you could be a "double diabetic." I think it is common for T1s to experience some insulin resistance through weight gain, so depending on your current weight, you might find that the resistance gets better with weight loss.

As for going on insulin, I was devastated at first. I was a complete needle-phobe before, and always considered T1 diabetes to be "the worst thing that could happen to me." Now, over 10 years later, I've gotten very used to it all. It still sucks, no doubt, but it's livable (and it beats the alternative)! If you do end up on insulin, I highly recommend getting a pump and CGM. They've helped me get my A1c down to the low 6s (possibly even lower - getting bloodwork next week).

What kind of healthcare provider are you? I've always heard that you guys make the worst patients ;-)

I'm always happy to help! Please keep us posted on your status - I'll be interested to read what your results show.

I followed the link to the details of how you had to fight for a correct diagnosis. As Type 1 (and 1.5) diabetics we have enough struggles. We need doctors who cooperate and listen to our questions, observations, and concerns. Some of us do our own research and reading. And besides that -- we live with diabetes 24/7/365. Doctors should respect that resume!

I had to fire one endo that did not want to cooperate with me. I view the doctor/patient relationship as a partnership where I am the senior partner. I respect the doctor's professional knowledge but they need to respect my "experience credentials" as well.

I recently asked my endo for the c-peptide, antibodies, insulin level and protein test to know where after 18 years which type I am. Currently my A1C levels are within 6.2 and 6.5 during this year. So I got the results for the c-peptide test and the insulin levels results. I know that C-Peptide levels if they are high you are probably a type 2, and if they are low you are probably a type 1. I got my results in the normal range( 3.20 ng/ml) of 1.1 to 3.3 ng/ml with a glucose fasting level of 133mg/dl. The insulin level was of 27.1uIU/ML, the lab range from 1.9 to 23 uIU/mL. I have to make a note that 12 hours before I injected my dose of insulin. I did not know if that would had and effect also I am still waiting for the other two results. Although I have a hunch I am diabetic type 2 and the only thing that has controlled my diabetes has been insulin only these past 5 years.




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