C-Peptide Response to Glucose, 3 Specimens
Test code
CPT code(s)*
Test resources
Details
Methodology
Immunoassay (IA)
Specimen requirements | |
|---|---|
| Patient preparation | Patients should fast 12 hours prior to collection |
| Preferred specimen(s) | 1 mL serum per specimen |
| Minimum volume | 0.5 mL per specimen |
| Collection 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. |
| 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 available |
| Reject criteria | Gross hemolysis • Plasma |
Reference Range(s)
| 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 | |
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
*The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.
The tests listed by specialty and category are a select group of tests offered. For a complete list of Quest Diagnostics tests, please adjust the filter options chosen, or refer to our Directory of Services.