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22796 Insulin, Free & Total (INSFT)

Insulin, Free & Total (INSFT)
Test Code: FINSUSO
Synonyms/Keywords
​Ref Lab Code: 81728, Free Insulin, Serum
Useful For
​Management of diabetes mellitus when the patient has known insulin autoantibodies
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​Yes Serum​ Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1 mL​ 0.5 mL​ ​
Collection Processing Instructions
Centrifuge sample within 2 hours of collection.  Pour off serum and ship frozen in a plastic transfer vial.  Patient shuld be fasting a minimum of 8 hours. If multiple specimens are drawn, send separate order for each specimen.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ Frozen (preferred)​ 180 days​
​ Refrigerated ​ 7 days​
Rejection Criteria
​Gross hemolysis
​Autopsy/postmortem specimen
 
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories​
 Monday through Saturday​
1 day​
Automated Chemiluminescent Immunoenzymatic Assay System​
Reference Lab
Mayo Clinic Laboratories
Reference Range Information
Insulin, Free, S: 2.6-24.9 mclIU/mL
Insulin, Total, S: 2.6-24.9 mclIU/mL
Interpretation
​During prolonged fasting, when the patient's glucose is reduced to <40.0 mg/dL, elevated insulin level plus elevated levels of proinsulin and C-peptide suggest insulinoma.
 
In patients with insulin-dependent diabetes mellitus, insulin levels generally decline.
 
In the early stage of noninsulin dependent diabetes mellitus (NIDDM), insulin levels are either normal or elevated.
 
In the late stage of NIDDM, insulin levels may also decline as levels of proinsulin decrease.
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
83525​
 ​ ​1 ​Insulin, Total, Serum ​
​83527 ​ ​1 ​Insulin, Free, Serum ​
Synonyms/Keywords
​Ref Lab Code: 81728, Free Insulin, Serum
Ordering Applications
Ordering Application Description
​Centricity ​Free Insulin
​Cerner ​Free Insulin (8128)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​Yes Serum​ Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1 mL​ 0.5 mL​ ​
Collection Processing
Centrifuge sample within 2 hours of collection.  Pour off serum and ship frozen in a plastic transfer vial.  Patient shuld be fasting a minimum of 8 hours. If multiple specimens are drawn, send separate order for each specimen.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ Frozen (preferred)​ 180 days​
​ Refrigerated ​ 7 days​
Rejection Criteria
​Gross hemolysis
​Autopsy/postmortem specimen
 
Useful For
​Management of diabetes mellitus when the patient has known insulin autoantibodies
Reference Range Information
Insulin, Free, S: 2.6-24.9 mclIU/mL
Insulin, Total, S: 2.6-24.9 mclIU/mL
Interpretation
​During prolonged fasting, when the patient's glucose is reduced to <40.0 mg/dL, elevated insulin level plus elevated levels of proinsulin and C-peptide suggest insulinoma.
 
In patients with insulin-dependent diabetes mellitus, insulin levels generally decline.
 
In the early stage of noninsulin dependent diabetes mellitus (NIDDM), insulin levels are either normal or elevated.
 
In the late stage of NIDDM, insulin levels may also decline as levels of proinsulin decrease.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories​
 Monday through Saturday​
1 day​
Automated Chemiluminescent Immunoenzymatic Assay System​
Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
83525​
 ​ ​1 ​Insulin, Total, Serum ​
​83527 ​ ​1 ​Insulin, Free, Serum ​
For most current information refer to the Marshfield Laboratory online reference manual.