Click here for more information about laboratory operations and procedures
Insulin, C-peptide
| Item | Value | ||
|---|---|---|---|
| Test Update Information | Effective March 15, 2011, C-peptide testing is being performed in-house using the same instrument-methodology (Siemens Centaur) that was used by Quest Diagnostics. | ||
| Approval req'd? | No | ||
| Available Stat? | No | ||
| Test code | CPEP | ||
| Performed by | China Basin Chemistry | ||
| Sendout? | Yes | ||
| Method | Chemiluminescent Immunoassay (Siemens Centaur) | ||
| Patient Preparation | Overnight fast is required before specimen collection. | ||
| Collection Instructions | Deliver to lab immediately. Call physician if patient is not fasting to see if the specimen is acceptable. | ||
| Container type | Gold top or Red top | ||
| Amount to Collect | 2 mL blood | ||
| Sample type | Serum | ||
| Preferred volume | 1 mL serum | ||
| Min. Volume | 0.4 mL serum | ||
| Processing notes | Separate serum from cells within 30 minutes of collection and freeze specimen at -20C. | ||
| Units | ng/mL | ||
| Normal range |
Reference range was adopted from Quest Diagnostics-San Juan Capistrano based on in-house validation studies performed using the same instrument-methodology (Siemens Centaur) on samples from adult subjects with normal FBS (70-99 mg/dL) and A1c (4.3-5.6%). Note: if patient was not fasting the normal ranges may not apply. Pediatric reference ranges not available for this immunoassay platform. |
||
| Synonyms | C-peptide | ||
| Stability | Room temperature 1 day, refrigerated 1 week frozen at -20C 4 weeks, at -70C 1 year. | ||
| Turn around times | Test performed Thursdays. | ||
| Additional information | Obesity, high carbohydrate diet and inactivity increase levels of this hormone. The assay is cross-reactive with proinsulin, but not with insulin. C-Peptide is useful in distinguishing insulin-secreting tumors, i.e., insulinomas, from exogenous insulin administration. C-Peptide concentrations are severely depressed or absent in Type I diabetes mellitus. It is also useful in monitoring patients who have received islet cell or pancreatic transplants. |
||
| CPT coding | 84681 | ||
| LOINC code | 1986-9 | ||
| Last Updated | 9/19/2012 8:48:35 AM | ||
| Entry Number | 148 | ||
| Lab Procedure Link | Click here for Procedure Click here for Vendor Package insert |
If you have additional questions regarding this test, please call: 415-353-1667