Insulin C peptide
Cpep
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
C-peptide, a cleavage product of proinsulin, is released in equimolar amounts with endogenous insulin and is used to assess pancreatic β-cell function. The primary reason for measuring C-peptide is to evaluate insulin production, particularly in distinguishing between type 1 and type 2 diabetes, assessing residual insulin secretion, and guiding treatment decisions such as insulin initiation. It is also essential in the diagnostic workup of hypoglycemia. In suspected insulinoma or islet cell tumors, elevated insulin and C-peptide levels during hypoglycemia suggest endogenous hyperinsulinism, whereas low C-peptide with high insulin supports exogenous insulin administration. C-peptide testing is valuable in patients with insulin autoantibodies, where direct insulin measurement may be unreliable. Due to its longer half-life and renal, rather than hepatic, clearance, C-peptide provides a more stable reflection of insulin secretion for laboratory analysis.
References:
Jones, A. G., & Hattersley, A. T. (2013). The clinical utility of C-peptide measurement in the care of patients with diabetes. Diabetic Medicine, 30(7), 803–817. https://doi.org/10.1111/dme.12159
Leighton, E., Sainsbury, C. A., & Jones, G. C. (2022). A practical review of C-peptide testing in diabetes. Diabetes Therapy, 13(1), 17–29. https://doi.org/10.1007/s13300-021-01174-7
Statement on Medical Necessity
All ordered tests should be medically necessary for the diagnosis or detection of disease, illness, impairment, symptom, syndrome, or disorder and the results should be used in the medical management and treatment decisions for the patient. Solaris requires ICD-10 codes with each order for lab testing and both the tests ordered and the diagnosis should be documented in the provider’s medical record for the patient. The United States Department of Health and Human Services, Office of Inspector General, takes the position that a provider who orders medically unnecessary tests may be subject to civil penalties.
Panels and Profiles
Solaris offers Providers the convenience of ordering test combinations in a group at times with the flexibility to choose appropriate test(s) for individual patients. Providers should only order those tests that he or she believes are medically necessary for each patient, and a lesser inclusive profile or individual tests should be ordered if not all tests in the test combination/profile are medically necessary. All tests offered in a test combination/profile may be ordered separately as individual tests. Solaris encourages clients to contact their Solaris representative if the testing configurations shown do not meet individual needs for any reason, or if some other combination of procedures is needed.
CPT Codes
CPT Codes listed are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are the responsibility of the billing party and are listed here for informational purposes. Correct coding may vary from one carrier to another. Solaris may bill specific carriers using codes other than what is shown.
For questions or inquiries related to testing please reach out to
customerservice@solarisdx.com or contact us by phone at (844) 550-0308.
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