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Interpreting urine cpeptide/creatinine ratio

Discussion in 'Type 1.5/LADA Diabetes' started by AnnM99, Aug 23, 2021.

  1. AnnM99

    AnnM99 · Well-Known Member

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    Hi guys,
    After a 2 week wait.. My results are in for the above test.
    It just says 'satisfactory'
    What on earth is this supposed to mean???? Other tests say 'normal'.
    There are numbers but I don't understand.
    Any thoughts appreciated.
    Thanks in advance.
     
  2. LaoDan

    LaoDan Type 2 · Well-Known Member

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    Some tests are like that, I had one test come back as “unremarkable”. I deviated as I believe I am remarkable lol. I wanted an A+ or something

    get the actual numbers and do the research. Most likely it’s in some normal range
     
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  3. Dark Horse

    Dark Horse · Well-Known Member

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  4. AnnM99

    AnnM99 · Well-Known Member

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    Thanks guys. Says ratio is 6.85 but have googled. Still confused. Will call surgery but not expecting much of a response.
     
  5. EllieM

    EllieM Type 1 · Moderator
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    Are there any units attached to the ratio?
     
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  6. AnnM99

    AnnM99 · Well-Known Member

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    Just this but no idea what it means and noone has been in touch. They never do tbh.
    Urine C Peptide Urine C Peptide analysed by:
    Clinical Biochemistry Dept
    Royal Devon and Exeter Hospital
    Urine C-peptide/creatinine ratio 6.85 nmol/mmol
    Random Urine C Peptide 15.08 nmol/L
    Urine creatinine level 2.20 mmol/L
     
  7. LaoDan

    LaoDan Type 2 · Well-Known Member

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    From my understanding, the results show that you are insulin resistant. Typical of T2s

    Edit, I think this test is to rule out a T1 diagnosis..
    others will probably know more
     
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  8. AnnM99

    AnnM99 · Well-Known Member

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    Yes that's
    Hi,
    Yes that's exactly right.... To rule out type 1. It says the result is satisfactory. Noone calls/explains about anything.
     
  9. LittleGreyCat

    LittleGreyCat Type 2 · Well-Known Member

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    I had no idea that this test even existed!
    I wonder how it is priced relative to a venous blood c-peptide?
    Noting especially that it is taken two hours after a meal, whereas the IR test that I had a while back was a fasting test.
     
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  10. Daibell

    Daibell LADA · Master

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    Hi. I also had my Urine C-Peptide tested this year by Exeter. Results were:
    Urine C-Pep/CR Ratio 0.79 nmol/mmol
    Random Urine C-Peptide 3.55 nmol/L
    Urine Creatinine level 4.5 mmol/L

    My C-Peptide is just above T1 level. As yours is a lot higher it seems to imply you are T2. The urine tests as opposed to blood serum are rather strange and consultants tend to use the Ratio as the determining factor for T1 versus T2 diagnosis rather than the C-Peptide. Creatinine is very variable from day to day so these measurements are not that accurate. My wife has just had a kidney transplant and I've learned a lot about Creatinine from her frequent blood tests! Incidentally my blood serum results from my annual tests show my Creatinine level to be very low (good) and yours appears to be even better.
     
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  11. ert

    ert Type 1 · Well-Known Member

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    Your results are normal rather than just above T1. The Urine C-Pep/CR Ratio need to be below 0.2 nmol/mmol for type 1. Anything above is normal. They should be interpreted with blood sugar and not on their own also.

    'The urinary C-peptide creatinine ratio is a practical non-invasive method to aid detection of absolute insulin deficiency, with a urinary C-peptide creatinine ratio > 0.2 nmol/mmol being a reliable indicator of retained endogenous insulin secretion.'

    https://pubmed.ncbi.nlm.nih.gov/236... non,of retained endogenous insulin secretion.
     
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  12. Fenn

    Fenn Type 1.5 · Well-Known Member

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    So
    Sorry I've tried so hard to sit on my hands following this, Can the test be wrong do you know?
     
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  13. KK123

    KK123 Type 1 · Well-Known Member

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    I've always found the C Peptide a tad confusing. I remember at the start my Nurse said my C peptide level (from blood) was '149', I don't have a clue what measurements she was using but she said it was the 'low end of normal'. One of the antibody tests was positive too (GAD) and along with general presentation and an hb1ac of 16% and impending DKA, they said type 1. I still wonder about that Peptide test though (4 years ago) to the extent I may try and get it tested again.
     
  14. Oldvatr

    Oldvatr Type 2 · Expert

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    That paper you provided the link for is puzzling. It only used test subjects who are already using insulin treatment, so may not read across to T2D on orals. Not sure why they base predictions on this particular ratio. C-pep being low or close to zero is a marker for endogenous insulin deficiency, and will always dominate this ratio. i,e, 0 /n =0 regardless of n.

    Several problems I see with this testing philosophy. Firstly, c-pep measures the insulin response to the meal. It is very dependant on there being trigger for the insulin response, and this requires carbohydrates in the diet. It therefore may not apply to those doing keto or LC diets, or intermittent fasting. Presumably, the follow-up test using the mixed meal is necessary to ensure that a standardised carb inclusive meal is used, but again it may be misled by long term LC use unless the person carbs up beforehand (as is required for the OGTT test)

    We recently had another thread that ended up discussing creatinine as a biomarker for kidney failure, and it appears in this diagnostic tool as well. Several scientific papers and articles were posted in that thread that showed that creatinine is directly affected by several confounders
    1) Only created directly by protein metabolism in the diet. No protein, no creatinine
    2) significantly higher values if the protein is from animal sources, rather than plant-based.
    3) affected by water intake - different results if the water is drunk to end a fast or dehydration, or if drunk with the meal.
    4) the kidney test is taken at 2hrs, this ratio is at 90 mins
    5) Level of exercise or exertion.

    Creatinine is a byproduct of an amino acid called creatine which is essential for the creation and repair of muscle tissue. Creatinine is related to having excess to requirements load, and is probably not determined by the meal just eaten at 90 mins, but will reflect previous meals and activity.

    Given the predominance of c-pep in the ratio at the trigger level, it is probably not going to have much effect but may skew borderline cases.

    So I question why a carb-based value is being compared to a protein excess-based parameter since they are chalk and cheese. What is also not taken into account is that kidney failure reduces the excretion of creatinine into the urine, and this will have a significant impact on this ratio.

    My take from the study report linked above is the time to start insulin treatment report and the BMI association report which are included in the washup at the end. So TOFI T2D beware! Your path to full progression would seem to be faster than normal T2D with extra padding. But there were only 9 subjects out of 191 in the cohort showing this, so based on a low sample size and possibly an unreliable observation.
     
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  15. ert

    ert Type 1 · Well-Known Member

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    The HOMA formula for beta-cell function are more useful in diagnosis rather than c-peptide as unless it's below 0.2 nmol/mmol (or really high) it won't be conclusive.
     
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  16. Seacrow

    Seacrow LADA · Well-Known Member

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    Unless it's at an extreme value, the c-peptide tells you very little. Take my results, at diagnosis cpep was "low", a couple of years later it was undetectable, a year ago it was "normal". Hang on, NORMAL? Test was redone, and came back normal again. My consultant was interested, and asked for antibodies. Positive. So according to the tests I'm a type one diabetic with normal insulin production.
    My conclusion? Don't believe the cpep values.
     
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  17. Fenn

    Fenn Type 1.5 · Well-Known Member

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    Wow, so the test is useless.
     
  18. Daibell

    Daibell LADA · Master

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    Hi. Yes I've read all the blurb and papers about using the urine ratio and I believe it's highly suspect. I had a private blood serum C-Peptide done a couple of years back and it showed me just above the T1 level which doesn't compare with the NHS Urine ratio test result. I'm slim (BMI 22), my body fat and visceral fat measures are low using gym measuring equipment and I use quite high levels of MDI insulin otherwise my BS rockets up as my Libre 2 shows. I fit all the patterns for LADA. My Urine ratio results appear absurd? I plan to have another serum C-Peptide in the near future done privately to try to get a formal T1 diagnosis on the books then may be one day I can have a Libre 2 without self-funding it :)
     
  19. ert

    ert Type 1 · Well-Known Member

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    You need to use the HOMA calculations which are more helpful as they show deterioration of beta cells as a percentage. (What my specialist used normally but my insulin production was too low to use the formulas when I was first diagnosed.) Otherwise, you will have to keep having c-peptide tests, and just having inconclusive results, waiting until the day you only have trace insulin (c-peptide below 0.2 ng/ml) and high blood sugars.

    The deterioration of beta cells isn't linear for type 1's. On diagnosis, my c-peptide was 0.17 ng/ml (type 1 diagnosis below 0.2) and blood sugar 18 mmol/l. I got my blood sugars down through low carb and running and one meal a day. My c-peptide plateaued for 2 years without changing. Then overnight my blood sugars shot up high with ketones of 5+, and I needed insulin and my c-peptide was 0.078 ng/ml (which is producing no insulin). I had GAD antibodies again (the first lot disappeared after 6 months) which supports my immune system killed off the rest of my beta cells. They did not deteriorate I just had two separate autoimmune responses killing them off on two different dates. This is on my specialist's report. I have private medical insurance so had an appointment every 3 months after I was diagnosed until I started insulin. I'm just looked after by the hospital team now (but my specialist is the head of the hospital team.)
    https://www.dtu.ox.ac.uk/homacalculator/
     
    #19 ert, Aug 25, 2021 at 5:18 PM
    Last edited: Aug 25, 2021
  20. Daibell

    Daibell LADA · Master

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    Hi. Thankyou. I will have a look at the HOMA information. Life is difficult when diagnosed as T2 and with a negative GAD. My brief referral to the county diabetes team and consultant was fruitless as they are obsessed with GAD results and mine is negative. In my case I believe I suffered a virus due to a high white cell count shortly before diagnosis and viruses are one known cause of beta cell death but not widely recognised. Many aspects of diabetes remain in the early days of understanding.
     
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