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HelpEpic Test Code LAB828 Insulin, Serum
Additional Codes
MML Code: INS
NY State Approved
YesPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Insulin, SMethod Name
Electrochemiluminescence Immunoassay (ECLIA)
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 180 days | |
| Refrigerated | 7 days |
Ordering 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. 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.
2. Fasting (8 hours)
Supplies: Sarstedt Aliquot Tube, 5 mL (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. Within 2 hours of collection centrifuge and aliquot serum into a plastic vial.
Additional Information: If multiple specimens are drawn, send separate order for each specimen.
Specimen Type
SerumSpecimen Minimum Volume
0.75 mL
Reference Values
2.6-24.9 mcIU/mL
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html.
Report Available
1 to 3 daysDay(s) Performed
Monday through Saturday
CPT Code Information
83525
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Autopsy specimen | Reject |
Useful For
Diagnosing insulinoma, when used in conjunction with proinsulin and C-peptide measurements
Management of diabetes mellitus
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 less than 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.
Cautions
In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. The presence of antibodies to streptavidin or ruthenium can also rarely occur and may also interfere in this assay. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.
Hemolysis interferes with this assay, as insulin-degrading peptidases are released from erythrocytes.
This assay has 100% cross-reactivity with recombinant human insulin (Novolin R and Novolin N). It does not recognize other commonly used analogues of injectable insulin (ie, insulin lispro, insulin aspart, and insulin glargine).