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Insulin, Free and Total, Serum

Test Codes

EPIC: LAB1230035, Beaker: XINS1, MAYO: INSFT

Department

Send Outs

Instructions

The patient should be fasting (8 hours) prior to specimen collection.

For 12 hours prior to blood collection, do NOT take multivitamins or supplements containing biotin (Vitamin B7).

Specimen Collection Criteria

Collect (preferred specimen): One plain Red-top tube.

Also acceptable: One Gold-top SST tube.

Send specimen for processing immediately after collection.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes and centrifuge to separate serum from cells within 2 hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 2.5 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.75 mL)

Rejection Criteria

• Hemolyzed specimens.
• Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes and centrifuge to separate serum from cells within 2 hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 2.5 mL serum, refrigerate (2-8°C or 36-46°F). (Minimum: 0.75 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 180 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Medical Laboratories, Rochester, MN.

Performed

Monday – Friday.
Results available in 1-4 days.

Reference Range

Free: 3-25 mcIU/mL
Total: 3-25 mcIU/mL

Test Methodology

Electrochemiluminescence Immunoassay.

Clinical Utility

Patients who have been injecting non-human insulin for treatment of insulin-dependent diabetes may develop insulin autoantibodies. These antibodies bind directly to insulin making it unavailable for metabolic activity. Free insulin levels can be useful in management of diabetes mellitus patients with known insulin autoantibodies.

CPT Codes

83527, 83525.

Contacts

Last Updated

12/24/2024