If you were offered a c-peptide test

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Lucyr

Lucyr

Well-Known Member
Relationship to Diabetes
Type 1
Probably more relevant to the T2s / MODY / LADA or misdiagnosed, so the T1s might need to use your imaginations.

If you could have a c-peptide test, after a long time of being classed as a type 2 on insulin, would you do it? Would your potential emotions at the result affect whether you’d do the test or not?

I’m not sure how I’d feel depending on the result. If my cpeptide was low and I found I was a misdiagnosed T1 then that would have big benefits. If it came out normal, that would be confusing but hopefully someone would know what it meant. If it came out high, and confirmed the ‘definitely a standard T2’ I don’t know how I’d feel, disappointed probably. Some may feel happy perhaps at the potential getting off insulin if can reduce your insulin resistance.

Would your potential reaction affect whether you’d have the test, if it was offered?
 
There’s an argument that all T2s should have tests for IR and c-peptide, in order to determine ‘phenotype’ and find a better treatment. (i.e. high IR, low beta cell functionality, high IR and normal beta cell function, and low IR but deficient insulin production.)

I’d be happy to get a high c-peptide result (And low IR) as it means removing insulin resistance would its possible to reverse the condition.

’Classic Type 2’ is a low insulin production and high insulin resistance. I wouldn‘t be so happy with this, as reversal is not as clear cut and it means a degree of beta cell dysfunction which may or may not be reversable. (I suspect I am in this boat, though.)

The other type is ’low insulin production’ and low/no insulin resistance. This is normally ‘slim’ type 2s, which wasn’t me, as I was somewhat rotund upon diagnosis!
 
I did Lucy. I was misdiagnosed as type 2 for 8 years. I was walking 6 miles a day just to keep my bloodsugars under 9mmol by mealtimes. I ended up on insulin. Couldnt keep weight on as i was burnibg all my calories. I remeber quite often thinking that it would be easier if i was a type one. Then my gp pravtice changed hands and i was offered it. Sure enough it came back positive for LADA.
 
And i have terrible insuline resistance but a very high sensitivity to it at tge same time.
 
gillrogers said:
And i have terrible insuline resistance but a very high sensitivity to it at tge same time.
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What makes you say that you have terrible insulin resistance?
 
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gillrogers said:
And i have terrible insuline resistance but a very high sensitivity to it at tge same time.
Click to expand...
How does this work and what does it mean for your insulin doses?
 
I'd do it but then these days I'll take any test offered, if only for geeky interest.
 
rebrascora said:
What makes you say that you have terrible insulin resistance?
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DB nurses told me cos of needing the lyumjev and im now having to prebolus ontop of that after a year on it.
 
Lucyr said:
How does this work and what does it mean for your insulin doses?
Click to expand...
Its a nightmare lucy. Im on lyumjev (lispro with a rocket to kick it off) for bolusing. After a year on it im having to prebolus again. But once its got going im sensitive to it so have a relatively low carb/insulin ratio. Its makes it very difficult with my job as its sporadically active and i can take the glucose tabs with me and ill drop faster than they can keep up. Thats just hoovering.
 
I can understand the emotional dilemma you are in with this @Lucyr.
My C-pep result came back borderline and I needed the GAD to clarify the situation. Thankfully it was taken at the same time but take another month for the result to come back so I had another month of uncertainty hanging over me, but that is obviously a millisecond compared to the time you have been up in the air about your diagnosis and as you probably know, neither test is guaranteed conclusive.
Obviously if it was to come back as very low and you were able o persuade them to do GAD antibody test you might end up getting rediagnosed and be eligible for CGM or even a pump although you should be eligible for CGM now, but I think you would have more of a fighting chance.
If it showed moderate insulin production, do you feel it would reinvigorate your lifestyle efforts or disillusion you? I think what I am trying to say is that there are potential significant gains if you are Type 1, but what are the possible drawbacks if it goes the other way. I am guessing that you have insulin resistance regardless, but that Type 1 label would probably open doors for you and make life easier.

What I would say is that, if you are offered a C-Pep test and accept it, make sure it is a blood sample and not urine, as the blood test is more reliable, if logistically more difficult, in that the sample has to be frozen within I think, 20 mins of being drawn and sent off to the lab in that state. Usually it is just main hospitals which have the facilities to ensure that the sample is properly handled.

Would you consider having it done privately? I know you already fork out a lot for sensors but I just wonder if having it done separate of the NHS may make you feel less compromised, in that I imagine you can choose whether you wish to disclose the result to the NHS. I am just thinking of your recent consultant visit and how unsympathetic he was and you can imagine an "I told you so" sort of response from someone like that, if the test result didn't go in your favour.

Apologies if I am totally off track with any of my thinking there but just trying to put myself in your shoes having had a tiny element of this situation myself. I think once I started on insulin, I knew it was for life, but having that Type 1 diagnosis 3 months later definitely made me feel better about it.
 
The benefits of finding out that cpeptide is low are obvious (save money on sensors) and probably worth the risks of other results, I just was surprised by my nervousness at the idea of having the test when I really thought about it. It came up in an appointment today, if I get to a point of having results I’ll share them but won’t say much more about it for now.

If my cpeptide is normal or high then would have to consider MODY apparently, I’d not really heard of MODY so made a separate post about that. There's potential implications for family if it was MODY I guess.

If the cpeptide was high my main concern would be if insulin was removed from my prescription because i produce enough insulin. I get high bgs and ketones within a couple days of missing insulin and don’t fancy fighting a battle to keep insulin.
 
gillrogers said:
Its a nightmare lucy. Im on lyumjev (lispro with a rocket to kick it off) for bolusing. After a year on it im having to prebolus again. But once its got going im sensitive to it so have a relatively low carb/insulin ratio. Its makes it very difficult with my job as its sporadically active and i can take the glucose tabs with me and ill drop faster than they can keep up. Thats just hoovering.
Click to expand...
I don't think this makes you insulin resistant, it is just the speed or otherwise that your body absorbs the insulin. I am on Fiasp which is a similar fast acting insulin to Lyumjev and I still need to prebolus 45 mins before breakfast to prevent my levels spiking (It was 75 mins with NovoRapid) and 20 mins at other times of day. I don't consider this insulin resistance, my body just takes time to get it from the subcutaneous fat to the blood stream. You are on such tiny doses of insulin, I don't think it is accurate to say that you are insulin resistant. I believe you are just not absorbing it as quickly as you were, or perhaps your honeymoon period is coming to an end and you are producing less of your own, which would have kicked in quicker than the Lyumjev does, so now it seems to take longer perhaps because there is less endogenous insulin in the blood stream responding before the injected stuff. Of course I may be totally off the mark.
On a morning my injected insulin is fighting a battle with my liver which is churning out excess glucose and the insulin I inject has to overcome that tidal wave of glucose before it can deal with my breakfast. That isn't my cells refusing to open up and accept the glucose, it is just the tide of glucose from my liver, is working against my insulin. That is how I see it anyway.
 
i thought not absorbing it quickly enough was resistance from how db nurses explained it to me. I know if ive been very active say before dinner then i dont need to prebolus as long and can drop half a unit of bolus for the meal, same for breakfast if ive been working a bar the night before . But the next meal im back to prebolusing and the full bolus.
 
Lucyr said:
The benefits of finding out that cpeptide is low are obvious (save money on sensors) and probably worth the risks of other results, I just was surprised by my nervousness at the idea of having the test when I really thought about it. It came up in an appointment today, if I get to a point of having results I’ll share them but won’t say much more about it for now.

If my cpeptide is normal or high then would have to consider MODY apparently, I’d not really heard of MODY so made a separate post about that. There's potential implications for family if it was MODY I guess.

If the cpeptide was high my main concern would be if insulin was removed from my prescription because i produce enough insulin. I get high bgs and ketones within a couple days of missing insulin and don’t fancy fighting a battle to keep insulin.
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Yes, I saw your post about MODY although I think it is an unlikely option since there is no family history and it is very rare but also, from what I have read, it is unusual for MODY to need insulin. MODY testing is also much more expensive than Type 1 testing I believe and takes months to get results, so I am not sure what you would gain from that, either positive or negative. ie no guarantee of sensors on prescription, in fact possibly less likely that Type 2 on MDI.

They surely could not stop your insulin if C-pep result came back high. You are still having to overcome insulin resistance and there are plenty of other Type 2s on insulin and it isn't as though you don't really make an effort to manage your diabetes well and you have been following the advice of an NHS dietician to help you lose weight. I really can't see what else they can expect you to do...... but I can understand your concern, because like all of us, insulin keeps us alive and any possible threat to supply is scary. I really think that last consultant has knocked your self confidence in dealing with this and it is so unfair!
 
gillrogers said:
i thought not absorbing it quickly enough was resistance from how db nurses explained it to me. I know if ive been very active say before dinner then i dont need to prebolus as long and can drop half a unit of bolus for the meal, same for breakfast if ive been working a bar the night before . But the next meal im back to prebolusing and the full bolus.
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The exercise/extra activity causes your muscles to suck the glucose out of your blood stream to replenish their stores without the need for insulin and that will occur for up to 48 hours afterwards, and if you have just done exercise then your blood will be circulating more rapidly and therefore absorb the insulin quicker from the subcutaneous fat that you inject into, but the resistance is all about the cells of the body not wanting to take the glucose out of the blood stream and more insulin being needed to force the glucose into them.
 
harbottle said:
There’s an argument that all T2s should have tests for IR and c-peptide, in order to determine ‘phenotype’ and find a better treatment. (i.e. high IR, low beta cell functionality, high IR and normal beta cell function, and low IR but deficient insulin production.)

I’d be happy to get a high c-peptide result (And low IR) as it means removing insulin resistance would its possible to reverse the condition.

’Classic Type 2’ is a low insulin production and high insulin resistance. I wouldn‘t be so happy with this, as reversal is not as clear cut and it means a degree of beta cell dysfunction which may or may not be reversable. (I suspect I am in this boat, though.)

The other type is ’low insulin production’ and low/no insulin resistance. This is normally ‘slim’ type 2s, which wasn’t me, as I was somewhat rotund upon diagnosis!
Click to expand...

I was a "classic" type 2 I suspect.
Low insulin production, high insulin resistance.
Helped initially by stimulating insulin production with Januvia, and decreasing insulin resistance with exercise.
Then cleared out the visceral fat with weight loss to get my pancreas producing insulin normally, so dropped the Januvia, and cleared the insulin resistance with weight loss and exercise, so dropped all meds.

It would have been interesting to find out, and I like information, so yes, I'd be tested.
 
We are both in the same boat Lucy where our stories never really added up to the normal progression timeline and medications just plain not working very well and very rapidly stopping being effective at all.

I understand completely about how you feel. I discussed testing last appointment and I got the yeah sounds like a good idea, ill phone you back...months ago 🙄

I think you need to consider you have gotten insulin on a t2 tag and it is unlikely they will undo that with a c-pep result either way.
The stories I have read here about insulin being taken away and replaced with oral meds are based on assumed t1 on presentation and confirmed to be t2 meaning t2 meds have a chance of working and they should progress through the usual medication steps instead. You have done that already. Metformin alone wont suddenly start to work because of a blood test.

I know your area doesn't have guidelines in line with nice for CGM which is what we both need. I see your graphs and I know you get extreme highs and lows and if there was ever a clear case of need, you would be it.
Totally dumbfounded how places drag out putting recommendations into place :(

Take the test. See what comes of it. Worst case I guess is they say t2 that needs insulin. Carry on as you are now. Anything else that gets you access to tech - bonus.
I know a t1 tag would benefit you far more than the t2 tag as you are already insulin dependant and have been for a long time and you already carb count/dose adjust exactly the same as a t1 would so there is no change to treatment at all, just lots more support.
 
travellor said:
I was a "classic" type 2 I suspect.
Low insulin production, high insulin resistance.
Helped initially by stimulating insulin production with Januvia, and decreasing insulin resistance with exercise.
Then cleared out the visceral fat with weight loss to get my pancreas producing insulin normally, so dropped the Januvia, and cleared the insulin resistance with weight loss and exercise, so dropped all meds.

It would have been interesting to find out, and I like information, so yes, I'd be tested.
Click to expand...
It would have been interesting to test now to see if your pancreas is producing normal amounts of insulin, but you have to skip a dose of insulin for the test to make sure you have a high bg at test time, which may be difficult, and being diet controlled limited benefits as your pancreas is clearly doing something right
 
rebrascora said:
Yes, I saw your post about MODY although I think it is an unlikely option since there is no family history and it is very rare but also, from what I have read, it is unusual for MODY to need insulin. MODY testing is also much more expensive than Type 1 testing I believe and takes months to get results, so I am not sure what you would gain from that, either positive or negative. ie no guarantee of sensors on prescription, in fact possibly less likely that Type 2 on MDI.

They surely could not stop your insulin if C-pep result came back high. You are still having to overcome insulin resistance and there are plenty of other Type 2s on insulin and it isn't as though you don't really make an effort to manage your diabetes well and you have been following the advice of an NHS dietician to help you lose weight. I really can't see what else they can expect you to do...... but I can understand your concern, because like all of us, insulin keeps us alive and any possible threat to supply is scary. I really think that last consultant has knocked your self confidence in dealing with this and it is so unfair!
Click to expand...
The DSN I saw this week didn’t mention stopping insulin, it was only a concern because that awful doctor last time said getting off insulin is the only treatment that will work. When skipping a dose of basal gives me high bgs and ketones.
 
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