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c peptide
- Thread starter tizzy
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ert
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fasting
C-peptide is a widely used measure of pancreatic beta cell function. It's basically your 3-month average insulin. Specifically, a c-peptide level of less than 0.2 nmol/l on diagnosis is associated with a diagnosis of type 1 diabetes mellitus (T1DM). I don't know what the 'positive' means in your question, it's numerical. Positives: simple, quick, correlates with diabetes type.
Daibell
Master
Hi. I can only assume 'positive' means high i.e. T2 but positive has no real meaning with regard to c-peptide so you need to seek clarification.
Bluetit1802
Legend
Was it a c-peptide test that was "positive" or are you mixing it up with a GAD antibodies test?
Bluetit1802
Legend
Knowing which tests were done, and the actual numbers (with measurement units because there are a couple of different ones) is the only way to solve this.
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Hello there Tizzy. Coincidentally, I was looking up c-peptide for something else, but this is the first time I have seen a table of ranges and meanings anywhere, in such an easy to understand way.
The table comes from here: https://www.exeterlaboratory.com/test/c-peptide-plasma/
As I understand matters, the Exeter lab does an awful lot of tests for other areas, as well as locally
ert
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In terms of a 20-30 minute half-life of c-peptide, you're correct. Also correct is a normal person's c-peptide would change over time depending on what they were eating, but never falling below 1 nmol/l at fasting. Your c-peptide would indicate you are producing normal to high levels of insulin.
However, for type 1's or low insulin type 2's where you have an impaired beta cell function (the fasting or stimulated c-peptide result is used in the HOMA formula to calculate beta cell function), like mine where the beta cell function has remained at 30% of normal for the last two years, with the c-peptide result being the same, taken every three months. Absent C-peptide at any time confirms absolute insulin requirement and the appropriateness of Type 1 diabetes management strategies regardless of apparent causes. So my c-peptide will never be higher because of the limited number of beta cells working at their maximum capacity, fasting or stimulated, hence why my specialist considers the c-peptide average insulin production.
ert
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This is my favourite c-peptide article, if you're after numbers: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3748788/
In T2 you can have normal or high amounts of insulin, but you cannot use it properly. Your body somehow resists the insulin, which is why it's called insulin resistance.
According to @DCUKMod 's graph and your post you have high insulin production, a strong pointer to T2.
You are in fact a classic T2 over producer of insulin which means that as @Antje77 says you have insulin resistance. If your test was fasting then you really are overproducing so cut right down on the carbs. Check your blood sugars regularly.. are you taking any medication for T2?
tizzy
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Hi sorry for the late reply I’m on novo rapid and tressiba and not insulin resistant apparently ,I’m fast losing faith I must admit on Monday I was told type 1 then a letter arrives and I’m type 2 unfortunately I didn’t know I had to fast for the blood test and what’s really annoying is I was having the test to confirm type 1 for the libre ####
HSSS
Expert
You say “not insulin resistant apparently”. Where does this statement come from?
On what basis and by whom were you told type 1 Monday?
According to that chart even not fasting your levels are still high indicating likely type 2
Hi all who have posted on this post so far! Today I had to have another c peptide test to try to get further clarification on my uncertain diagnosis. I was told this time to get above 10 for the test. So before setting off for the hospital, I had a slice of white toast and of course didn’t inject my insulin. The highest I recorded about an hour and a half later was 19.6 (and I started at 8). I then corrected as quickly after. I just wondered what sort of rise others would get from eating a slice of toast and no insulin?
(I had taken my background insulin last night).
(I had taken my background insulin last night).
Circuspony
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My c peptide was done under a 2.5 hour session at the hospital. I took 70g of carbs and hit 20 after 2.5 hours.
Blood test taken at the same time showed v low c peptide which meant I wasn't producing much insulin (T1)
Do you know the c peptide result that was taken at the same time as that 19? If low you are likely T1 - although I also presented with 2 x positive antibody tests
Blood test taken at the same time showed v low c peptide which meant I wasn't producing much insulin (T1)
Do you know the c peptide result that was taken at the same time as that 19? If low you are likely T1 - although I also presented with 2 x positive antibody tests
I’m currently waiting in my c peptide result from the most recent test where my level was 19. My previous c peptide was low and my blood glucose was high (13.5). I’m assuming this time my c peptide will be even lower, but guess will wait and see!
