Clinical Report: Evaluating the Insulin-to-C-Peptide Molar Ratio for Differentiating IAS and EIAS

Overview

This study evaluates the diagnostic performance of the insulin-to-C-peptide molar ratio in differentiating insulin autoimmune syndrome (IAS) and exogenous insulin antibody syndrome (EIAS) from insulinoma.

Background

Insulin autoimmune syndrome (IAS) and exogenous insulin antibody syndrome (EIAS) can lead to severe hypoglycemia and may be misdiagnosed as insulinoma, resulting in unnecessary interventions. Accurate differentiation is crucial for appropriate management. The insulin-to-C-peptide molar ratio is a potentially useful diagnostic tool.

Data Highlights

Key Findings

• The insulin-to-C-peptide molar ratio was significantly higher in IAS and EIAS compared to insulinoma.
• During hypoglycemic episodes, the AUC for IAS versus insulinoma was 0.970.
• The optimal cutoff for IAS during hypoglycemic episodes was determined to be 0.382.
• In the fasting state, the optimal cutoff for EIAS was found to be 0.386.
• Insulin concentration alone also showed good diagnostic performance for IAS, with an AUC of 0.985 during hypoglycemic episodes.

Clinical Implications

The study suggests that clinicians should consider using lower cutoffs for the insulin-to-C-peptide molar ratio to improve diagnostic sensitivity for IAS and EIAS. This approach may help in avoiding misdiagnosis and unnecessary interventions in patients suspected of having insulinoma.

Conclusion

The insulin-to-C-peptide molar ratio is a valuable diagnostic tool for differentiating IAS and EIAS from insulinoma.

Related Resources & Content

1. Frontiers | Diagnostic utility of the insulin-to-C-peptide molar ratio in differentiating insulin autoimmune syndrome and exogenous insulin antibody syndrome from insulinoma
2. Non-Diabetic Hypoglycemia - Endotext - NCBI Bookshelf
3. The Journal of Clinical Endocrinology & Metabolism — Utility of the C-Peptide/Insulin Molar Ratio for Distinguishing Type A Insulin Resistance Syndrome From Type 2 Diabetes
4. Frontiers in Endocrinology — A Case Report and Literature Review of Proton Pump Inhibitors Inducing Insulin Autoimmune Syndrome
5. The Journal of Clinical Endocrinology & Metabolism — Autoantibody-Positive Nondiabetic Individuals: Investigating Insulitis and Exocrinitis in Relation to HLA Genotypes
6. The Journal of Clinical Endocrinology & Metabolism — Dedifferentiation of β-Cells in Individuals with Low and High HOMA-β Values
7. Non-Diabetic Hypoglycemia - Endotext - NCBI Bookshelf
8. Frontiers | Diagnostic utility of the insulin-to-C-peptide molar ratio in differentiating insulin autoimmune syndrome and exogenous insulin antibody syndrome from insulinoma