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HelpTest Code INS; SQ: INSULI Insulin, Serum
Reporting Name
Insulin, SUseful For
Diagnosing insulinoma, when used in conjunction with proinsulin and C-peptide measurements
Management of diabetes mellitus
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering Guidance
Patients on insulin therapy may develop anti-insulin antibodies. These antibodies may interfere in the assay system, causing inaccurate results. In such individuals, measurement of free insulin INSFT / Insulin, Free and Total, Serum should be performed.
Specimen Required
Patient Preparation:
1. Patient should be fasting.
2. For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Avoid hemolysis
2. Label specimens with corresponding collection times.
3. Centrifuge and aliquot serum into plastic vial within 2 hours of collection.
Additional Information: If multiple specimens are drawn, send separate order for each specimen.
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 180 days | |
| Refrigerated | 7 days |
Reference Values
2.6-24.9 mcIU/mL
For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday through Friday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
83525
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| INS | Insulin, S | 27873-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| INS | Insulin, S | 27873-9 |
Clinical Information
Insulin is a hormone produced by the beta cells of the pancreas. It regulates the uptake and utilization of glucose and is also involved in protein synthesis and triglyceride storage.
Type 1 diabetes (insulin-dependent diabetes) is caused by insulin deficiency due to destruction of insulin-producing pancreatic islet (beta) cells. Type 2 diabetes (noninsulin-dependent diabetes) is characterized by resistance to the action of insulin (insulin resistance).
Insulin levels may be increased in patients with pancreatic beta cell tumors (insulinoma).
Interpretation
During prolonged fasting, when the patient's glucose level is reduced to <40 mg/dL, an elevated insulin level plus elevated levels of proinsulin and C-peptide suggest insulinoma.
Insulin levels generally decline in patients with type 1 diabetes mellitus.
In the early stage of type 2 diabetes, insulin levels are either normal or elevated. In the late stage of type 2 diabetes, insulin levels decline.
In normal individuals, insulin levels parallel blood glucose levels.
To compare insulin and C-peptide concentrations (ie, insulin to C-peptide ratio):
-Convert insulin to pmol/L: insulin concentration in mcIU/mL x 6.945 = insulin concentration in pmol/L.
-Convert C-peptide to pmol/L: C-peptide concentration in ng/mL x 331 = C-peptide concentration in pmol/L.
Method Description
This insulin method is a sandwich electrochemiluminescence immunoassay that employs a biotinylated monoclonal insulin-specific antibody and a monoclonal insulin-specific antibody. Insulin in the specimen reacts with both the biotinylated monoclonal insulin-specific antibody (mouse) and the monoclonal insulin-specific antibody (mouse) labeled with a ruthenium complex, forming a sandwich complex. Streptavidin-coated microparticles are added and the mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell. Application of voltage to the electrode induces the chemiluminescent emission, which is then measured.(Package insert: Roche Insulin reagent. Roche Diagnostics; V1 10/2010)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Autopsy specimen | Reject |
Method Name
Electrochemiluminescence Immunoassay (ECLIA)