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C-Peptide
Test CodeLAB521
Quest Code
372
Alias/See Also
CPEPQ, CPEP, CPEPT
CPT Codes
84681
Preferred Specimen
1 mL serum
Patient Preparation
Patient should fast 12 hours prior to collection
Minimum Volume
0.5 mL
Instructions
Patient 12 hour fast is recommended but not required.
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 7 days
Refrigerated: 7 days
Frozen: 7 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Plasma
Methodology
Immunoassay (IA)
Setup Schedule
A.M.
Reference Range
0.80-3.85 ng/mL
Clinical Significance
C-Peptide is useful in the evaluation of pancreatic beta cell function (e.g., helping distinguish type 1 from type 2 diabetes mellitus, or monitoring patients who have received islet cell or pancreatic transplants) and for determining the source of insulin in patients with hyperinsulinemic hypoglycemia (e.g., distinguishing insulin-secreting tumors from exogenous insulin administration). It is also sometimes measured as an additional means (more resistant to hemolysis than is insulin itself) for evaluating glucose tolerance tests.
Performing Laboratory
Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042