Short fasting test as a reliable and effective tool to diagnose insulinoma

#3877

Introduction: Insulinomas are pancreatic NETs presenting with hypoglycaemia. Current guidelines for its diagnosis require a prolonged fasting test (72 hours), which implies hospitalization and is difficult to perform. It has been reported that up to 85% of insulinomas are diagnosed within a 24h fasting period.

Aim(s): To predict weather a shorter fasting test initiated overnight and portrayed up until 24h could be a sensitive method for diagnosing insulinoma.

Materials and methods: We conducted a retrospective monocentric study including all subjects with clinical suspicion for insulinoma admitted at the Endocrinology Unit of the Sant’Andrea Hospital from 2003 to 2022. 22 patients were submitted to the standard prolonged test (2003-2018) and 12 to the short fasting test (2019-2022). The latter initiates overnight at home, proceeding the following day in outpatient setting (Day Hospital). Blood is drawn for glycaemia, insulin and C-Peptide as in the standard test. Diagnostic values for insulinoma consist of glucose <55 mg/dL with insulin ≥3µU/mL and C-Peptide ≥0.6 ng/mL. In case of negative result and a remaining high suspicion for insulinoma, the prolonged test would be performed subsequently.

Conference:

Presenting Author: Mikovic N

Authors: Mikovic N, Mazzilli R, Zamponi V, Russo F, Faggiano A,

Keywords: insulinoma, neuroendocrine pancreatic tumor, functioning NET, hypoglycaemia,