Diagnosis and management of insulinoma

Table 1 Diagnosis of insulinoma

Classical diagnosis

Hypoglycemia (plasma glucose < 50 mg/dL)

Neuroglycopenic symptoms

Prompt relief of symptoms following the administration of glucose

Present consensus

At the time of hypoglycemia during a 72-h fasting test:

5 mIU/L (36 pmol/L) insulin threshold

0.6 ng/mL (0.2 nmol/L) C-peptide threshold

Insulin/C-peptide ratio < 1.0

20 pmol/L proinsulin cut-off level

Absence of sulfonylurea (metabolites) in the plasma or urine