Test Id : INSAL
Insulin Analogs, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Detection and quantitation of native human insulin and insulin analogs in serum
Assessment of factitious hypoglycemia from misuse or surreptitious administration of insulin analogs
Monitoring treatment adherence of prescribed insulin therapy
Providing an alternative testing methodology for insulin measurements when immunoassay test results do not align with the clinical presentation and/or interference is suspected
Method Name
A short description of the method used to perform the test
Liquid Chromatography Mass Spectrometry, High-Resolution Accurate Mass-Mass Spectrometry (LC-MS HRAM)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Synthetic Insulin
Pharmaceutical Insulin
Exogenous Insulin
Native Insulin
Human insulin
Novolin R
Novolin N
Aspart
NovoLog
Glulisine
Apidra
Lispro
Humalog
Admelog
Glargine
Glargine M1
Glargine M2
Lantus
Specimen Type
Describes the specimen type validated for testing
Serum Red
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Patient Preparation:
Fasting: 8 hours, required for human insulin reference values to apply
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red Top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL Serum
Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial
Additional Information: Human insulin reference values are not applicable to patients who were not fasting for 8 hours or received pharmaceutical/synthetic insulin analogs.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
Serum: 0.75 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen | 14 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Detection and quantitation of native human insulin and insulin analogs in serum
Assessment of factitious hypoglycemia from misuse or surreptitious administration of insulin analogs
Monitoring treatment adherence of prescribed insulin therapy
Providing an alternative testing methodology for insulin measurements when immunoassay test results do not align with the clinical presentation and/or interference is suspected
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Insulin is a peptide hormone that plays a critical role in regulation of blood glucose levels; thus, prescribed insulin therapy is widely used for treatment of type 1 or type 2 diabetes mellitus. However, a large and increasing proportion of clinically used insulin preparations are no longer based on naturally occurring insulin but are instead insulin analogs created using recombinant DNA technology to modify human insulin to alter its pharmacokinetics and pharmacodynamics. This results in insulin analogs with rapid onset and offset of action, or conversely, delayed onset but a concomitant delay in the offset of insulin action. Current immunoassays for insulin have been designed to detect the native (natural) form of human insulin in serum or plasma. No currently available insulin immunoassays detect these insulin analogs with the same reliability as natural insulin, while the degree of detection cross-reactivity with insulin analogs varies between different insulin immunoassays. Thus, insulin analogs present unique challenges when assessing patients exhibiting hypo- or hyperglycemia. This novel liquid chromatography-high-resolution mass spectrometry test overcomes the limitations of currently available immunoassays by enabling simultaneous detection and quantitation of native human insulin and the insulin analogs aspart, glulisine, lispro, and glargine. These measurements are beneficial for monitoring treatment adherence of prescribed insulin therapy in patients with diabetes and unexpected hyperglycemia. This test is also useful in assessment of patients with unexplained hypoglycemia and it is uniquely suited to identify factitious hypoglycemia caused by the surreptitious use of insulin analogs or insulin.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Human insulin: 2.6-24.9 mcIU/mL
Reference values only apply to fasting patients not being administered pharmaceutical/synthetic insulins.
Therapeutic reference intervals for synthetic insulin analogs have not been established.
Interpretation
Provides information to assist in interpretation of the test results
The human insulin reference values only apply to fasting patients not being administered pharmaceutical/synthetic insulins.
Detection of insulin analogs indicates exposure to insulin analogs, but the detection window and levels of insulin analogs after administration vary significantly based on the unique pharmacokinetics of the various insulin analogs. Intra- and inter-individual variability of insulin pharmacokinetics can also be significant.
Therapeutic reference intervals for insulin analogs have not been established.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test cannot currently detect or measure the long-acting insulin analogs detemir, degludec, or icodec.
This test cannot differentiate between endogenous human insulin and exogenous/synthetic forms of human insulin (Novolin R and Novolin N)
Human insulin reference values are only applicable to patients who are fasting and not being administered pharmaceutical/synthetic insulin analogs.
Hemolysis interferes with this assay, as insulin-degrading peptidases are released from erythrocytes.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Egan AM, Galior KD, Maus AD, et al. Pitfalls in Diagnosing Hypoglycemia Due to Exogenous Insulin: Validation and Utility of an Insulin Analog Assay. Mayo Clin Proc. 2022;97(11):1994-2004
2. Cryer PE, Axelrod L, Grossman AB, et al. Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2009;94(3):709-728. doi:10.1210/jc.2008-1410
3. Grunberger G, Weiner JL, Silverman R, Taylor S, Gorden P. Factitious hypoglycemia due to surreptitious administration of insulin. Diagnosis, treatment, and long-term follow-up. Ann Intern Med. 1988;108(2):252-257. doi:10.7326/0003-4819-108-2-252
4. Parfitt C, Church D, Armston A, et al. Commercial insulin immunoassays fail to detect commonly prescribed insulin analogues. Clin Biochem. 2015;48(18):1354-1357. doi:10.1016/j.clinbiochem.2015.07.017
5. Morello CM. Pharmacokinetics and pharmacodynamics of insulin analogs in special populations with type 2 diabetes mellitus. Int J Gen Med. 2011;4:827-835. doi:10.2147/IJGM.S26889
6. Lepore M, Pampanelli S, Fanelli C, et al. Pharmacokinetics and pharmacodynamics of subcutaneous injection of long-acting human insulin analog glargine, NPH insulin, and ultralente human insulin and continuous subcutaneous infusion of insulin lispro. Diabetes. 2000;49(12):2142-2148. doi:10.2337/diabetes.49.12.2142
7. Lutz Heinemann. Variability of insulin action: Does it matter?. Insulin. 2008;3(1):37-45. doi:10.1016/S1557-0843(08)80010-3
8. Van Der Gugten JG, Wong S, Holmes DT. Quantitation of insulin analogues in serum using immunoaffinity extraction, liquid chromatography, and tandem mass spectrometry. Methods Mol Biol. 2016;1378:119-130. doi:10.1007/978-1-4939-3182-8_14
9. Thevis M, Thomas A, Delahaut P, Bosseloir A, Schanzer W. Qualitative determination of synthetic analogues of insulin in human plasma by immunoaffinity purification and liquid chromatography-tandem mass spectrometry for doping control purposes. Anal Chem. 2005;77(11):3579-3585. doi:10.1021/ac050066i
10. Nedelkov D, Niederkofler EE, Oran PE, Peterman S, Nelson RW. Top-down mass spectrometric immunoassay for human insulin and its therapeutic analogs. J Proteomics. 2018;175:27-33. doi:10.1016/j.jprot.2017.08.001
Method Description
Describes how the test is performed and provides a method-specific reference
Insulin analogs are extracted from serum using an immunopurification followed by liquid chromatography separation and mass analysis using a high-resolution accurate mass-mass spectrometer.(Egan AM, Galior KD, Maus AD, et al. Pitfalls in diagnosing hypoglycemia due to exogenous insulin: Validation and utility of an insulin analog assay. Mayo Clin Proc. 2022;97(11):1994-2004. doi:10.1016/j.mayocp.2022.07.021)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees
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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
G0480
80375 (if appropriate for select payers)
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| INSAL | Insulin Analogs, S | In Process |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 624133 | Human | In Process |
| 624134 | Glargine M1 | In Process |
| 624135 | Glargine M2 | In Process |
| 624136 | Lispro | In Process |
| 624137 | Glulisine | In Process |
| 624138 | Aspart | In Process |