So I did a C-peptide and FBS today to see if it gave any useful information.

C-Peptide was 2.1 (1.1-4) and FBS was 108.

How do I interpret this?

1. Probably not insulin resistant (would expect that the C-peptide should be higher with the high FBS being a little high??).
2. Still producing some insulin.

Well, you do need to get a medical opinion, but I will tell you that you are still producing insulin. But after that, I have to tell you, the result is inconclusive. You can run your numbers through a calculator which uses a model to estimate remaining beta cell function (%B) and IR, but with a normal blood sugar, the results are not trustworthy. I am T2 and with a blood sugar of 135 mg/dl and a c-peptide that was 1.4 (or maybe 1.8), my doctor declared me insulin resistant. So go figure.

Still producing quite a lot of insulin. Good for you! I’d like to have mine rechecked. At my initial diagnosis my c-peptide was 0.7 and fasting levels were 400. Now with the honeymoon my levels are 100-120 without basal I’m wondering what my c peptide will show

Or perhaps, not knowing any more about your history than what's in this post--- it could mean that you are slightly insulin resistant after all? As your c-peptide appears to be pretty much in the middle of the normal range but your fasting glucose was slightly higher than optimal?

Yes, although I would refine the first part. A c-peptide in normal range with a normal FBS doesn't mean that you are "normal" it simply means that the test doesn't give any information about anything "abnormal." You could still be insulin resistant and even insulin deficient to a certain degree.

Why was the test done? it simply means you're producing enough insulin and your FBS of 108 is in no way high. you're a type 2, if that's what they were trying to determine. cpeptide doesn't have anything to do with insulin resistance or determine the level of it. type 1's can have insulin resistance too if they've been t1's depending on how many years they've been battling type 1, etc...weight, etc... you're producing normal levels of insulin. good for you!

Actually, yes, c-peptide can indicate insulin resistance. If you have a high c-peptide it means you are producing a lot of insulin but your body is unable to use it due to Insulin Resistance.

correct, however these tests don't indicate a high cpeptide, it's normal, within range. many t1's can develop insulin resistance and still will have zero cpeptide because they're type 1's.

Fasting BG wasn't really high. And yes, it means you're still producing a normal amount of insulin. So the first question that come to mind for me is, are you Asian? (I know you live in the Philippines). Asians develop T2 or insulin resistance at much lower BMIs than Caucasians do. The second one is, have you been tested for antibodies? That would at least give you an answer as to whether you are a LADA in honeymoon period, or a thin T2, which is common in Asians.

You are not producing an outlandish amount of insulin, but it's still in the normal range, so I think you need to ask your doc to dig a little deeper so as to find out what is the best treatment for you.

The fasting C-peptide that you spoke of in your original post SHOULD be enough to keep BGs normal. And the fasting BG that you indicated was in the pre-diabetic range, not diagnosable as diabetic. But I seem to remember that you had gestational diabetes, so you are clearly at risk. But don't think of that fasting BG as high, because it ISN'T. I don't know what your post-prandial BGs are like, but they can go up to the 160-180 range and still be considered normal or close to it.

If I were you, I would keep an eye on it, and be retested periodically, but not worth getting frantic over. You could have an A1c done, and it might reassure you if it's within normal range. I hope you can get over your fears, because I do understand that they are real.

Well, in a non-diabetic, a fasting c-peptide in the normal range should be enough to maintain normal fasting numbers. But we are of course diabetic, so things get messed up. And we have to remember, the fasting c-peptide may be just the "idling" output of the pancreas, or it could be the "top end." We just don't know.

So if we are insulin resistant, that level of insulin may not be enough to maintain a normal fasting. And our fastings are controlled by insulin and glucagon, and for many of us, all that signalling is messed up. I have had a number of "normal" c-peptides with elevated fastings (130-140 mg/dl) and without insulin, my fasting numbers are 120-160 mg/dl. So at least in my case, a "normal" c-peptide doesn't help me maintain normal fastings.

An A1c of 5.7 is normal, and Bernstein notwithstanding, I have read studies, particularly the one by Stefansson, of non-diabetic people that show postprandial values between 120 and 160.

So, while you need to keep an eye on it, and continue your efforts to eat well and exercise, it's not panic time just yet. And it doesn't matter what TYPE you are -- what matters is that you are maintaining a very good A1c. Type matters to academics doing studies, but in the clinical, practical world, all that matters is the proper treatment.

Before I got verification from medical professionals that I was T1 or something very close to it, I used to call myself Type Weird, because I never fit into any of the boxes. I finally decided that it REALLY doesn't matter -- what matters is that if I am hospitalized, that they don't kill me by withholding insulin. Which they tried to do, once upon a time.

So just keep on walking the good walk and talking the good talk, and live your life without obsessing over type, OK?