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Evaluation of endocrine tests. D: the prolonged fasting test for insulinoma

A C van Bon1, N Benhadi, E Endert

  • 1Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, the Netherlands. a.c.vanbon@amc.nl

The Netherlands Journal of Medicine
|August 19, 2009
PubMed

Insights

The prolonged fasting test, combining Whipple's triad and an insulin/C-peptide ratio <1, accurately diagnoses insulinoma. This test demonstrated 88.9% sensitivity and 100% specificity in suspected cases.

Area of Science:

  • Endocrinology
  • Clinical Diagnostics

Background:

  • Insulinoma diagnosis can be challenging.
  • Prolonged fasting tests are used to evaluate patients with suspected insulinoma.

Purpose of the Study:

  • To determine the diagnostic accuracy of the prolonged fasting test for insulinoma.

Main Methods:

  • Patients with suspected insulinoma underwent prolonged fasting.
  • Diagnosis was based on Whipple's triad and an insulin/C-peptide ratio <1.
  • Histopathology confirmed insulinoma; long-term follow-up was used for negative tests.

Main Results:

  • The test identified 8 out of 9 insulinoma cases (88.9% sensitivity).
  • Two cases of factitious hypoglycemia were correctly identified (100% specificity).
  • No insulinoma cases were missed during follow-up of patients with negative tests.

Conclusions:

  • The prolonged fasting test, with specific criteria, is a highly sensitive and specific diagnostic tool for insulinoma.
  • This diagnostic approach aids in differentiating insulinoma from other causes of hypoglycemia.
Abstract

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