C-peptide creatinine ratio (UCPCR): Urine

Blood Sciences Test

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Specimen

Random urine in Boricon container; measured on a post prandial sample taken approximately two hours after a meal stimulus.

Random non-fasting urine in Boricon container.

Special Instructions

Stable for 3 days in Boric acid containers at ambient temperature. If unable to send sample immediately, freeze at -20°C and send at ambient temperature in the post. For long-term storage (e.g. to batch samples), we recommend freezing at -80°C.

Units

nmol/mmol/L

Test Usage

Interpretation of Urine C-peptide Creatinine ratio

General points

UCPCR is mainly to be used in patients on insulin treatment to assess endogenous insulin secretion. Its role in patients not on insulin treatment is limited.
If the result of UCPCR is out of keeping with other clinical finding then we would recommend repeating the test especially if it is unexpectedly low. Patients tipping out boric acid preservative from urine collection tube, in a sample taking more than 3 days to reach the laboratory can result in artificially low results (McDonald 2009). We are not aware of any reason for a falsely high value.

Most of the studies have been performed in patients with normal renal function (eGFR >60 mL/min/1.73 m²) but it has been validated in patients with Type 2 diabetes with moderate renal impairment (eGFR 30-60 mL/min/1.73 m² (Bowman 2011). The test is unlikely to be appropriate in patients with severe renal impairment.

What values are expected in the different subtypes?

The urinary C-peptide creatinine ratio (UCPCR) result is best measured on a post prandial sample taken approximately two hours after a meal stimulus. Thresholds for interpretations of UCPCR in patients with insulin treated diabetes are shown below (TABLE 1)

For random non-fasting urine collections, results are strongly correlated with mixed meal C-peptide, with high sensitivity and specificity for identifying clinically relevant thresholds.

If you have any further enquiries please contact Tim McDonald by email: Timothy.McDonald@nhs.net

References

• Hope SV, Knight BA, Shields BM, Hattersley AT, McDonald TJ, Jone AG. Random non-fasting C-peptide: bringing robust assessment of endogenous insulin secretion to the clinic. Diabet Med. 2016 Nov;33(11):1554-1558. PubMed PMID: 27100275.
• McDonald TJ, Knight BA, Shields BM, Bowman P, Salzmann MB, Hattersley AT. Stability and Reproducibility of a Single-Sample Urinary C-Peptide/Creatinine Ratio and Its Correlation with 24-h Urinary C-Peptide. Clin Chem. 2009 Nov;55(11):2035-9. Clin Chem. 2009 Nov;55(11):2035-9. Epub 2009 Aug 27.
• Bowman P, McDonald TJ, Shields BM, Knight BA, Hattersley AT. Single sample Urinary C-Peptide/Creatinine Ratio (UCPCR) is a reproducible alternative to serum C- peptide in patients with Type 2 diabetes.Diab Med
• Jones AG, Besser REJ, McDonald TJ, Shields BM, Hope SV, Bowman P, Oram RA, Knight BA, Hattersley AT. Urine C-peptide creatinine ratio (UCPCR) is an alternative to stimulated serum C-peptide measurement in late onset insulin treated diabetes. Diabetic Medicine. Epub ahead of print 2011 Jan 2010
• Besser REJ, Ludvigsson J, Jones AG, McDonald TJ , Shields BM, Knight BA, Hattersley AT. Urine C–peptide creatinine ratio (UCPCR) is a non-invasive alternative to the mixed meal tolerance test in children and adults with Type 1 diabetes. Diabetes Care. 2011 Mar;34(3):607-9. Epub 2011 Feb 1.
• Besser REJ, Shepherd MJ, McDonald TJ, Shields BM, Knight BA, Ellard S, Hattersley AT. Urinary C-peptide creatinine ratio (UCPCR) is a practical outpatient tool for identifying HNF1A/HNF4A MODY from long duration Type 1 diabetes. Diabetes Care. 2011 Feb;34(2):286-91.

Availability

Local test

Turnaround Time

7 days

Cannot be added on to an existing request

 

REFERRALS

We welcome referrals for UCPCR. If you are a new requestor please complete the following form: New requestor form

We now also have the option to use NPEx for referral requesting.

Further information about sample requirements for this test can be found here: Urine C Peptide – further information

Further information about sample labelling requirements for this test can be found here: Specimen Labelling Procedure

Specimen Labelling Procedure