Accurate selection of insulin immunoassay to discern factitious hypoglycemia: a case report

Factitious hypoglycemia in insulin-treated diabetic patients

“…Discrepancy in serum insulin measurements suggests the presence of insulin analogs. The interfering analogs can then be identified by LC-MS/HRMS when available [4]. In all instances, active collaboration between medical biologists and clinicians helps disentangle complex situations.…”

“…We recently reported the case of a 20-year-old women with a 5-year history of poorly controlled type-2 diabetes, treated with metformin and insulin pump therapy (insulin aspart, Omnipod pump, Insulet Corporation, USA), who was admitted for acute hyperglycemia without ketosis (blood glucose 25 mmol/L, HbA1c 12.2%) [4]. On day 4 following admission, episodes of hypoglycemia occurred and became more frequent even after insulin infusion was decreased and stopped.…”

“…Therefore, 2 blood samples collected during a hypoglycemic episode were analyzed with the Immulite 2000 Xpi system (Siemens Healthcare, Saint-Denis, France). On this method, insulinemia was significantly elevated, suggesting the presence of an insulin analog (see Table 1 in ref [4]). To confirm this hypothesis, samples were sent for specific identification of insulin analogs by the LC-MS/HRMS method.…”

“…), which must first be considered. Moreover-and this is one message we would like to pass on-insulin and C-peptide measurements may provide inconsistent or misleading results, depending on the cross-reactivity of the insulin quantification assays with the specific insulin analog used to induce hypoglycemia [3][4][5][6][7][8].…”

Cross-Reactivity of Insulin Immunoassays Important for Insulin Analogue Detection in Factitious Hypoglycaemia

“…This makes it challenging to identify these alterations in the assays due to their low cross-reactivity with insulin immunoassays. [ 4 ] Roche Elecsys assay does not exhibit any cross-reactivity with any insulin analogues, but they are picked up with Abbott analyser. Understanding the differences in cross-reactivities between different analysers and insulin analogues is crucial when interpreting insulin assays and evaluating hypoglycaemia.…”