Mini-fasting Tests Diagnosing Endogenous Hyperinsulinism: a Follow-up of 26 Cases

Abstract

Context:

The supervised 72-h fast remains the gold standard test for the diagnosis of endogenous hyperinsulinism and has recently been suggested to be shortened or even avoided.

Objective:

This study aimed to evaluate whether measurement of blood glucose, insulin and C-peptide levels after a 12 h overnight fast (mini-fasting test), in at least 3 consecutive days, could allow making or ruling out diagnosis of endogenous hyperinsulinism, according to the Endocrine Society’s recent guidelines.

Patients and methods:

We performed 12 h mini-fasting test in at least 3 consecutive days, dosing blood glucose, insulin and C-peptide levels in 26 inpatient patients with pathologically proven endogenous hyperinsulinism.

Results:

In our series, 100% of patients showed insulin levels of at least 3 μU/ml and C-peptide levels of at least 0.6 ng/ml concomitant with symptomatic hypoglycemia (≤55 mg/dl).

Conclusion:

It leads to the conclusion that mini-fasting test might avoid, in most cases, prolonged fasting test for the diagnosis of hypoglycemia due to endogenous hyperinsulinism.

Key words

endocrine pancreas - hypoglycemia - insulinoma

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