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C-peptide - fasting or no fasting? + Diagnosis now put into more doubt

N

notepadplusplus

Well-Known Member
Messages
58
Type of diabetes
Other
Treatment type
Diet only
Hi everyone,

This week has started off quite confusing now. I was happy to receive what sounded like a pretty firm diagnosis of an autoimmune variant of diabetes last Friday due to positive IA-2 antibodies (negative GADA though) and the fact I am 22. Happy because finally, after a 1 month of waiting I can put an actual name to the disease I have to live with for the rest of my life.

For context, I am in the latter end of the overweight stage in terms of BMI, and I've responded incredibly well to a low-carb/ketogenic diet losing approx 1.5 stone in a month. My average fasting BG is 4.3 mmol/L, and my fasting ketones are averaging in the low 4s.

The Diabetes SpR at the local hospital telephoned me today and now things sound a lot less certain. Paraphrasing what they said, but it was something along the lines of "You have risk factors for Type 1 because of your age and antibodies, but also for Type 2 because of your ethnicity and weight. I think we will likely diagnose you as Type 2 presenting with signs of Type 1". The thing is, I'm not sure what's going on now and how this will potentially impact my treatment plan.. I have a proper first review at the clinic next week, so I hope I can get some clarity then.

So I'll be going into the clinic to have my blood pH and bicarbonate tested to see if the ketone bodies are making my blood more acidic. I think a c-peptide is also going to be done as well, but they questioned the usefulness of that result as it's clear I am producing insulin on my own. I also asked if I should eat something before the test or if I should fast, but they said it's fine to eat before the c-peptide especially because my fasting BG is on the low end of normal. Is this the case? Everything I've read online seems to mention a fasting c-peptide rather than eating before.

I suppose the most concerning thing for me is that they've said having IA-2 antibodies means I'll likely have to take insulin in the future, but how will I catch that stage early when being diagnosed as T2 means I'll probably no longer have access to testing strips? Surely, waiting 12-months for my next HbA1c test to be conducted just to be told I'll need to be put on insulin means irreparable damage will be done?

I guess I'm just looking for some certainty here and I'm getting quite anxious. If I was a T2DM without any antibodies present then I wouldn't even be making this thread and I'd carry on with keto without fuss, but potentially being told I'm in fact not T1DM but instead T2DM "with antibodies" and a high chance of needing insulin in the future despite my current efforts concerns me a lot, given how differently the NHS treats T1s vs T2s from what I've seen (less testing, more spaced out reviews etc).
 
I'm afraid we can't diagnose you. In type 2 diabetes, the presence of IA-2A is infrequent and predicts the future need for insulin therapy is written about: https://pubmed.ncbi.nlm.nih.gov/15765222/
However, with your age, antibodies, and blood sugars on diagnosis, I don't see how they can be sure you are not type 1 on honeymoon. You certainly qualify for a referral pathway to a specialist. Your weight loss and keto diet could be extending your honeymoon. Non-fasting c-peptide tests are common, but may be inconclusive as your BS's are currently normal. I hope you get a clearer diagnosis soon.
 
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Thanks for this

I do have an appointment with the consultant next week. I was told it was being brought forward to this week... but that doesn't seem to be the case after the call with the SpR. Hopefully I'll get some more clarity then!
 
Reactions: ert
As far as I understand, and it's been a while since I looked into it, being on a keto diet and having perfectly healthy blood glucose doesn't help diagnosing you.
When your BG is low, but your C-peptide is too, it will only show your insulin production was sufficient at that moment, BG being normal means you don't need more insulin at the time of testing.
Eating very few carbs, wether non diabetic, T2 or a honeymooning T1 means you need very little insulin so no need for your body to produce more than a little insulin. This means that in a situation where you need little insulin there is no way to tell if your C-peptide is low because you cannot produce more insulin but what you produce is enough because of your diet (T1) or if your C-peptide is low because you don't need to produce more insulin (healthy situation).

If I remember correctly a BG of at least 8 is adviced for a C-peptide test to see if you react to a higher BG by producing more insulin. If you don't, T1. If you do, T2 or honeymooning T1. So possibly still inconclusive.
I'm sorry to not have links to the sources on this, like I said, it's from memory from when I was having similar questions.

Not an ideal solution, but should this happen, what about testing only a couple of times a week to keep an eye on your numbers suddenly rising as expected in T1 so you can alert the diabetes team if this happens? As long as your numbers are this low you don't need treatment, regardless of type. They might decide to prescribe test strips based on your positive antibodies, or you can buy test strips yourself. Not fair, but better than waiting for a yearly test!
 
A c-peptide test post meal (Around 45mins after) should show how well your pancreas is responding to the meal. Sounds like a real mess of a situation, I hope you get it cleared up real soon. Good luck.
 
Tophat1900 said:
A c-peptide test post meal (Around 45mins after) should show how well your pancreas is responding to the meal. Sounds like a real mess of a situation, I hope you get it cleared up real soon. Good luck.
Click to expand...
Antje77 said:
Unless it's a very low carb meal, which wouldn't need an insulin a response, which could be an issue in this situation.
Click to expand...

I'll be sure to have some brown bread then. I've been upping my carbohydrates a bit anyway over the weekend on the advice from the Consultant through the GP as my fasting ketones are apparently a bit too high.
 
C peptide can confuse issues if honeymooning as on the day the test is done your cpeptide might be perfectly normal.. the following day it may not be

So cpeptide with other results alongside each other... and continued monitoring for changes

It took 10 years for me to be classed type 1 from diagnosis
 
Quick update:

Just been to the clinic for the tests. My ketones have come waaaaaaay down since loading up on carbs for today so the SpR is happy that the ketones aren't due anything else other than being low carb.

Diagnosis still unclear of course, but I have another appointment next week. Unfortunately, the c-peptide is going to take several weeks apparently! Must be out of reagent or the labs are all booked up for Covid-19 tests.

Definitely feel a lot more rubbish now that my body has switched back to glucose/carbohydrate burning rather than ketones. Hopefully, I won't get the keto-flu this time round (not that it was that bad last month anyway)
 
Hi @notepadplusplus, I was told at the start of diagnosis not to change my eating habits to begin with (ie going low carb) because that would make it more difficult for them to see how my body was responding to certain things. For example, going low carb (especially keto) would require your body to produce less insulin so when they do a C Peptide test (checking to see how much insulin you may still be producing), it would tell them you were producing less than you might otherwise have been 'naturally'.

Going low carb immediately would likely result in a lower hb1ac result months later (great generally speaking) but not so great when they are trying to establish how your body is reacting to carbs. Some Consultants/GPs might then view that as 'oh, here is someone without diabetes, or they are type 2 rather than type 1 or vice versa'.

A dramatic change in your lifestyle of old as it were, can mask the diagnosis. I imagine they will get there eventually but it could take longer.

I don't know for sure with your positive antibodies (I think type 2s can also have them???) but in your shoes I would not want to be left with 'you are type 2 we think but you may need insulin later because of your antibodies' as I believe the presence of antibodies is a strongish marker for defining one type from another. If you ARE type 1 then you may not wish to have to soldier on without insulin steadily getting worse. It's complicated !!! x

(EDITED; posted this just before your update so don't know if still any use x ).
 

Thanks for this! It does make a lot of sense.

I don't want to be left in such a position either - I spend time on polar opposites of the country being a university student, so suddenly needing insulin when I'm in London would be a complete and utter nightmare!


10 years, wow!
 

Hi there, you seem very on the ball with it all so that is a massive bonus! I am sure you aim to keep testing so that should tell you where you are as you are going along waiting for your further tests, etc. Just one comment, if you ever see your glucose levels going very high at the same time ketones are high, please seek medical advice. Ketones can be dietary of course but if you suddenly add high levels of glucose to the mix it can be extremely dangerous (DKA). x
 
You may by now have worked out what your body is doing. I was diagnosed 7 years ago, totally unexpected, no history in family or anything. at first they thought type 2 and put me on Metformin tables, they did not sit well with me. 3 months later I had pains in my legs and not well and turned out I had a Ketoacidosis issue, which got sorted out in hospital on drops and they then decided I was actually type 1. Now getting Ketoacidosis does not happen to everyone (but I do live in rural Scotland and I think it was a case of they did not monitored me close enough in early days), but my point is in the early stages it can take time for things to progress and to work out exactly what is going on and which camp you will fall into. I understand this “pre diabetes or early stage can in some people take 18 months before the body levels to what is happening. Even then it can take months to get treatment and doses right for best management. It can be a very confusing time and if you are anything like me you go into overdrive looking for all the answers! Don’t expect too much of yourself trying to work it all out too quickly, keep a certain amount of open mindedness and digest and analysis bit by bit. I would have thought loosing weight was a good move, as long as you don’t loose it too fast, although appreciate it will make it harder for medical professionals to pin things down. Stay calm, all will become clearer ...... in time. You are barely just starting out on the honeymoon period as some call it.
 
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