Fasting Insulin Test results

[Hans Langer]

Hi All

I had a fasting insulin test done at a specialist clinic here to try and understand what exactly my problem is, ie insulin resistant, insulin deficient, or both. These are the results

Time Glucose C-Peptide Insulin
0 min 4.6 163 1.1
30 min 9.7 864 13.7
60 min 13.7 1516 14.7
90 min 15.1 1993 17.7
120 min 15.2 2317 18.8

The problem I have is how to interpret the C-Peptide and Insulin figures. There is no indication in the results what the units of measurement might be. If insulin is micro-units per mililitre then that's an incredibly low fasting insulin level, and if it's pmol/l, it's even lower still. Whichever it is, doesn't seem to indicate insulin resistance.

Any help/insights greatly appreciated!

 

[Northerner]

Hi Hans, I can't claim to know what the figures mean myself, but this page may be useful:

http://labtestsonline.org/understanding/analytes/insulin/tab/test

The page says that in order to interpret the results then you need to know the reference range, which can be dependent on a number of factors so can't be given absolute values. You would need to have the lab test report to know what the reference ranges were - do you have the report?

 

[RachelT]

Hi Hans,

At a guess, and it is just a guess because i'm not a doctor, but judging from a very vague knowledge of blood tests and how to find them on wikipedia, i would suggest that since your c-peptide and insulin levels are clearly rising with the level of glucose in your system that your pancreas is still producing insulin (whether this is enough insulin i don't know) and thus you're type 2. You'd need an expert or a doc to tell if the levels are less than those on a non-diabetic person an thus whether your're insulin resistant or not producing enough of the stuff.

Sorry, that's not a whole lot of help

Rachel

 

[trophywench]

Well I think it shows that your pancreas is certainly responding to higher glucose levels but if exogenous insulin was sufficient then surely your BG would have been lower throughout?

I have a firiend who actually got a C-peptide test last year as it had never been established whether she was T1 or T2 and I do remember her C-pep level was 80.4 with "normal" being 350 to 1100 odd. That made her resoundingly T1.

If it's the same lab test range then your results must surely mean that you are producing a lot of insulin but it isn't working very well which would then indicate insulin resistance - but we don't know that. ISTR from somewhere in the depths of my brain that a non-diabetic produces approx 20u a day. So if there's 13.7u circulating after 2 hours, that again might indicate lot's of insulin that isn't doing a lot to help you.

But this is entirely speculation.