Cardio IQ® Insulin Resistance Panel with Score

Test Code

LAB6589

Quest Code

36509

Alias/See Also

LAB6589

CPT Codes
83525, 84681

Includes

Insulin, Intact, LC/MS/MS
C-Peptide, LC/MS/MS
Insulin Resistance Score

Preferred Specimen

0.5 mL serum

Patient Preparation
Overnight fasting is required

Minimum Volume

0.3 mL

Instructions

Collect blood samples observing routine precautions for venipuncture. Allow serum samples to clot completely before centrifugation.

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 24 hours

Refrigerated: 7 days

Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Hemolysis

Methodology
Immunocapture Liquid Chromatography/Tandem Mass Spectrometry

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Night

Reference Range

Insulin, Intact, LC/MS/MS	≤16 uIU/mL
C-peptide, LC/MS/MS	0.68-2.16 ng/mL
Insulin Resistance Score	≤66

Clinical Significance

The determination of insulin in serum is primarily used for the diagnosis of glycemic disorders in diabetic and pre-diabetic patients in the assessment of insulin resistant syndromes. Insulin is synthesized by the pancreatic beta cell as a precursor, proinsulin. Proinsulin is processed to insulin and C-peptide, a contiguous peptide between the insulin A and B chains, as it passes through the cell. The C-peptide in the proinsulin ensures correct folding and processing of proinsulin as it passes through the cell. Both insulin and C-peptide are released together from the beta cells in response to increased glucose levels. Because of differences in half-life and hepatic clearance, peripheral blood levels of C-peptide and insulin are no longer equimolar but remain highly correlated. A steady-state plasma glucose test in individuals undergoing an insulin suppression test to assess insulin resistance found that the combination of insulin and C-peptide was a better indicator of insulin resistance than either one individually.

Performing Laboratory
Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.