Insulin productivity

Hiya fullfathomfive!

I'm no expert in this, but my understanding is that there are two tests that can be done (although I think they are generally done to check for insulin resistance rather than how much insulin you are producing as such). Anyway, they are c-peptide test and fasting serum insulin test.

I think the c-peptide test is based on the fact that insulin starts off in two linked parts; c-peptide and insulin. Therefore if they find you are producing c-peptide, you must be producing insulin. The levels of c-peptide tell them how much insulin. Generally they use the test along with a fasting blood glucose test. High c-peptide + high blood glucose = insulin resistance (and is usually indicative of Type 2 diabetes). However, it can also tell them the level to which those of us with LADA are still producing our own insulin and can help to monitor the progression of the condition into full Type 1. The main advantage of this test over the Fasting Insulin Serum test is that it can still be used if you are injecting insulin. Injected insulin does not contain c-peptide and so any c-peptide in your body must be derived from your own insulin production.

The Fasting Serum Insulin test is more accurate (I think) than the c-peptide test and is used to measure actual insulin levels in the blood stream. However, it cannot differentiate between natural insulin and injected insulin, so it is not suitable for those of us who are injecting insulin.

As I say, I'm not an expert in this, but this is what I've understood from conversations with my consultant.

Hope that helps a bit.

Incidentally, I'm LADA and that is classified by some consultants as Type 1 (by others as Type 1.5). Anyway, I still produce insulin - sometimes quite a lot of it, other times not so much - every day is a lottery :lol: I just try to inject the right dose for how my pancreas is reacting at any given time. So this might be similar to what's happening with you? The other thing that could be affecting things is insulin resistance. If you sometimes have a bit of insulin resistance, you will need to inject more insulin to get the required effect - but if you do a bit more exercise one day, have different hormone levels, eat differen food, lose a bit of weight (all sorts of things!), you might find that your insulin resistance decreases and your injected insulin works more effectively - perhaps this could be giving you the impression that you are producing some insulin?

Hope you get it sorted out.

Smidge

I don't know that testing would be very helpful because you are taking insulin so the results would be hard to detect if the insulin came from you or was injected. Do you keep a diary of things you have been doing and then see if there is a relationship between activities and the lows. Sometimes an activity or exercise could have an effect the next day or even later. You may still be producing some of your own insulin but most people with diabetes have sudden changes for no apparent reason from time to time. I even alter my sons basal insulin for winter and summer.

I'm getting the results of the anti-bodies test (c-pep) on the 30th at Steno. After 13 months being type 1, a Dr. Suspects I might be something else! Frustrating as heck. I produce 840 c-pep, but non-functional. I am on levemir (26) and novo rapid(30) a day. I adjust on training days down ass the insulin is more effective under exercise.... But as a newbie age 47 this is a **** irritating illness

Tri-Dude said:

But as a newbie age 47 this is a **** irritating illness

Click to expand...

Unfortunately it can be just as irritating after 30+ years :roll:

Hi Tri Dude
Can I ask what the Dr thought it might be out of interest? Is it Type !.5 or type 2 they are thinking?

Could you or anyone explain the C-pep test please, ie what the levels are for Type 1?

Thanks

I think I came out with 847 c-peptide and the hospital determined I am indeed a Type 1 (drat) but whilst no-one can ever prove it, it's likely I'm a LADA. Well, it's blindingly obvious to me, in hindsight. LADA is, in the WHO listings, simply a type of Type 1 - there's no real need to call it anything else, it's just classic (autoimmune) Type 1 that comes on slowly, inconsistently and often affects older people than the usual age group for Type 1, which is children, teenagers and young adults. I was 36 at diagnosis. To be clear about the c-peptide, I asked them what it meant, and whilst it does show a low level of insulin, it's too low - and considered diabetic. To prove once and for all whether you're a Type 1 or not, you also need some other tests including the set of antibody tests. If you're making antibodies, you're a Type 1, because this means you have the autoimmune process at play. However, sometimes you make them and sometimes you don't - so a negative test still doesn't exclude Type 1 (I was negative for them at diagnosis), but a positive result tells you that's what it definitely is. So when I had that c-peptide test, 2yrs into the whole thing, I also had the antibody tests and they were positive, and that was the thing that showed I was ultimately a Type 1.

Sorry to be super-super-clear about the c-peptide - Type 2s can also have low readings so you can't say there's a specific level that says you're Type 1 or 2 etc - this is why you have to have other tests too.