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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
C-Peptide Response to Glucose, 3 Specimens
Test Code15844
CPT Codes
84681 (x3)
Preferred Specimen
1 mL serum per specimen
Patient Preparation
Patients should fast 12 hours prior to collection
Minimum Volume
0.5 mL per specimen
Instructions
Draw fasting specimen. Administer oral glucose solution (1.75 g/kg body weight or 75 g maximum). Collect 1 mL serum for each timed specimen post glucose dose. All tubes must be clearly marked with time drawn. Submit all tubes with one test requisition.
Reference ranges available: Fasting, 30, 60, 90, 120, 150, 180, 240 and 300 minutes post glucose.
Reference ranges available: Fasting, 30, 60, 90, 120, 150, 180, 240 and 300 minutes post glucose.
Transport Container
Transport tube(s)
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen -20° C: 7 days
Frozen -70° C: Not established
Refrigerated: 7 days
Frozen -20° C: 7 days
Frozen -70° C: Not established
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Plasma
Methodology
Immunoassay (IA)
Setup Schedule
Set up: Mon-Sat; Report available: Next day
Reference Range
| Fasting | 0.80-3.85 ng/mL | |
| 30 minutes post glucose | 1.78-7.49 ng/mL | |
| 60 minutes post glucose | 1.91-8.21 ng/mL | |
| 90 minutes post glucose | 1.52-7.95 ng/mL | |
| 120 minutes post glucose | 1.19-6.04 ng/mL | |
| 150 minutes post glucose | 1.06-5.98 ng/mL | |
| 180 minutes post glucose | 1.06-3.88 ng/mL | |
| 240 minutes post glucose | 0.86-3.22 ng/mL | |
| 300 minutes post glucose | 0.86-2.50 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.
