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Pitfalls in Diagnosing Hypoglycemia Due to Exogenous Insulin

Validation and Utility of an Insulin Analog Assay
Published:October 07, 2022DOI:



      To overcome the limitations of commercially available insulin immunoassays which have variable detection of analog insulin and can lead to clinically discordant results and misdiagnosis in the workup of factitious hypoglycemia.

      Patients and Methods

      We performed analytical validation of a liquid chromatography high resolution accurate mass (LC-HRAM) immunoassay to detect insulin analogs. We completed clinical assessment using a large cohort of human serum samples from 78 unique individuals, and subsequently used the assay in the evaluation of eight individuals with high diagnostic suspicion for factitious hypoglycemia.


      The performance characteristics show that the LC-HRAM immunoassay can be applied to detect five commonly used synthetic insulin analogs (lispro, glulisine, aspart, glargine metabolite, and detemir) in human serum. Our clinical cases show that this assay could be used in the diagnosis of factitious hypoglycemia by identifying the analog insulin(s) in question.


      The LC-HRAM immunoassay reported here overcomes a gap in our diagnostic pathway for hypoglycemia. The results obtained from our studies suggest that this method is appropriate for use in clinical laboratories when factitious hypoglycemia is considered as a differential diagnosis.

      Abbreviations and Acronyms:

      CMSL (Clinical Mass Spectrometry Laboratory), LC-HRAM (liquid chromatography high resolution accurate mass), MS (mass spectrometry)
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        • Service F.J.
        Hypoglycemic disorders.
        N Engl J Med. 1995; 332: 1144-1152
        • Whipple A.
        The surgical therapy of hyperinsulinism.
        J Int Chir. 1938; : 237-276
        • Sheldon B.
        • Russell-Jones D.
        • Wright J.
        Insulin analogues: an example of applied medical science.
        Diabetes Obes Metab. 2009; 11: 5-19
        • Owen W.E.
        • Roberts W.L.
        Cross-reactivity of three recombinant insulin analogs with five commercial insulin immunoassays.
        Clin Chem. 2004; 50: 257-259
        • Heald A.H.
        • Bhattacharya B.
        • Cooper H.
        • et al.
        Most commercial insulin assays fail to detect recombinant insulin analogues.
        Ann Clin Biochem. 2006; 43: 306-308
        • Nalbantoğlu Elmas Ö.
        • Demir K.
        • Soylu N.
        • Çelik N.
        • Özkan B.
        Importance of insulin immunoassays in the diagnosis of factitious hypoglycemia.
        J Clin Res Pediatr Endocrinol. 2014; 6: 258-261
        • Reyes Barron C.
        • Augustine M.
        • Zhang Y.V.
        Recurrent hypoglycemic episodes with hypoinsulinemia in a patient with diabetes.
        Clin Chem. 2021; 67: 345-348
        • Thomas A.
        • Thevis M.
        Analysis of insulin and insulin analogs from dried blood spots by means of liquid chromatography-high resolution mass spectrometry.
        Drug Test Anal. 2018; 10: 1761-1768
        • Peterman S.
        • Niederkofler E.E.
        • Phillips D.A.
        • et al.
        An automated, high-throughput method for targeted quantification of intact insulin and its therapeutic analogs in human serum or plasma coupling mass spectrometric immunoassay with high resolution and accurate mass detection (MSIA-HR/AM).
        Proteomics. 2014; 14: 1445-1456
        • Oran P.E.
        • Jarvis J.W.
        • Borges C.R.
        • Sherma N.D.
        • Nelson R.W.
        Mass spectrometric immunoassay of intact insulin and related variants for population proteomics studies.
        Proteomics Clin Appl. 2011; 5: 454-459
        • Nedelkov D.
        • Niederkofler E.E.
        • Oran P.E.
        • Peterman S.
        • Nelson R.W.
        Top-down mass spectrometric immunoassay for human insulin and its therapeutic analogs.
        J Proteomics. 2018; 175: 27-33
        • Parfitt C.
        • Church D.
        • Armston A.
        • et al.
        Commercial insulin immunoassays fail to detect commonly prescribed insulin analogues.
        Clin Biochem. 2015; 48: 1354-1357
        • Kao S.L.
        • Chan C.L.
        • Tan B.
        • et al.
        An unusual outbreak of hypoglycemia.
        N Engl J Med. 2009; 360: 734-736
        • Duncan G.G.
        • Jenson W.
        • Eberly R.J.
        Factitious hypoglycemia due to chlorpropamide. report of a case, with clinical similarity to an islet cell tumor of the pancreas.
        JAMA. 1961; 175: 904-906
        • Klonoff D.C.
        • Barrett B.J.
        • Nolte M.S.
        • Cohen R.M.
        • Wyderski R.
        Hypoglycemia following inadvertent and factitious sulfonylurea overdosages.
        Diabetes Care. 1995; 18: 563-567
        • Jaghab K.
        • Skodnek K.B.
        • Padder T.A.
        Munchausen's syndrome and other factitious disorders in children: case series and literature review.
        Psychiatry (Edgmont). 2006; 3: 46-55
        • Giurgea I.
        • Ulinski T.
        • Touati G.
        • et al.
        Factitious hyperinsulinism leading to pancreatectomy: severe forms of Munchausen syndrome by proxy.
        Pediatrics. 2005; 116: e145-e148
        • Service F.J.
        • Rubenstein A.
        • Horwitz D.L.
        C-peptide analysis in diagnosis of factitial hypoglycemia in an insulin-dependent diabetic.
        Mayo Clin Proc. 1975; 50: 697-701
        • Schade D.S.
        • Drumm D.A.
        • Eaton R.P.
        • Sterling W.A.
        Factitious brittle diabetes mellitus.
        Am J Med. 1985; 78: 777-784
        • Ford C.
        Deception syndromes: Factitious disorders and malingering.
        in: Ford C.V. The American Psychiatric Textbook of Psychosomatic Medicine: Psychiatric care of the Medically Ill. American Psychiatric Publishing, Inc, 2011
      1. Hamilton J, Feldman M. Factitious disorder and malingering. Washington, DC, USA 2007.

      Linked Article

      • Explaining Unexplained Hypoglycemia Due To Insulin Analogs
        Mayo Clinic ProceedingsVol. 97Issue 11
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          Hypoglycemia is a potentially life-threatening condition that requires urgent medical attention. Most hypoglycemia in patients with diabetes is related to medication use, and recent studies have indicated the contributions of insulin analogs in cases of hypoglycemia.1,2 Even in patients without diabetes, it is important to exclude insulin administration as a cause of hypoglycemia, yet detection of insulin analogs is not straightforward. The small structural changes that result in favorable pharmacokinetics of insulin analogs also affect the detection of analog insulin by immunoassays, culminating in varying results from different commercially available assays.
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