Endocrine Abstracts

Introduction: One of the manifestations of Munchausen syndrome is the deliberate injection of insulin to achieve hypoglycemia or artificial hypoglycemia. If human insulin is injected, we will always determine high level of insulin and low level of Cpeptideatthemomentofhypoglycemia. Incasesof insulin analogues injection the diagnos is maybe difficult when we use analyzers specific only to human insulin: the low level of IRI and C peptide will be determined.

Objectives: Tocomparethediagnosticaccuracyof analyzers AbbottArchitect (AA) andRoche (R) in determining the IRI levelafterinjectionthe insulin analogues.

Methods: 120 patients with suspected NDH aged 18–80 wereincludedin a cross-sectional study. According to the results, we selected the patients (n = 14) with hypoinsulinemic hypoglycemia (glucose less than 2.8 mmol/l, C peptide less than 0,6 ng/ml, IRI less than 3 µU/ml), diagnosed by the R kit. Then we determined the IRI level in the same blood sample using AA kit.

Results: IRIlevelsaccordingtothedataofdifferentanalyzers were different, but in 93% of cases (n = 13) the differences were not clinically significant; the diagnosis did not changed (hypoinsulinemic hypoglycemia). Onlyinone patient we revealed significant change of IRI level (more than 2000%): 1.91 µU/ml by theR kit and 42 µU/ml by the AA kit. Taking into account the level of Cpeptide lessthan 0.6 ng/mlwe diagnosed the artificial hypoglycemia. In addition, we found the injection marks on the patient body. The patient was referred to a psychiatrist’s consultation. The causes of hypoinsulinemic hypoglycemia in the other patients in our study are: non-β-cell tumors, adrenal and hepatic insufficiency.

Conclusion: inthecasesofusingkits, that determine only human IRI, if the deliberate injection of insulin analogues is suspected (hypoinsulinemic hypoglycemia), for the confirmation the diagnosis it is advisable to investigate the same blood samplewith hypoglycemia using kits, that also determine insulin analogues, forexample, the analyzer AA. Duringtheanalyze of the IRI levels it is required to take into account the C peptide value, which will be always low in cases ofdeliberate injection of any insulin.

Funding: The grant of Russian Science Foundation (project 17-75-30035).