Differential diagnosis of documented spontaneous
hypoglycaemia. The measurement of both insulin and C-peptide
is undertaken since in some cases of insulinoma, insulin levels may
be low whereas C-peptide is almost always unequivocally
raised. Both measurements are required for the identification
of factitious insulin observation.
The use of insulin and C-peptide levels to assess endogenous
insulin production in Type 2 diabetics is unreliable and should be
restricted to patients awaiting renal/pancreatic transplant.
Request on ICE
Analysed by referral laboratory if specific criteria met.
Differential diagnosis of documented spontaneous hypoglycaemia.
Samples will not normally be analysed unless simultaneous glucose
analysis shows hypoglycaemia (< 2.5 mmol/L by laboratory
Assessment of endogenous insulin production for patients awaiting
For investigation of hypoglycaemia, a grey top (fluoride) sample
must be taken simultaneously.
For assessment of endogenous insulin production: exogenous insulin
suppresses endogenous insulin production. Suggested procedure is to
withhold usual pre-meal insulin, give light meal and collect
samples after 30 mins. Usual insulin dose can then be given.
SST serum AND glucose sample
Samples must be transported to laboratory immediately.
Patients MUST be bled at Southend hospital
Sent to referral laboratory (Royal Surrey County Hospital)
Causes for Rejection
Not meeting specific criteria for analysis; delay in sample
reaching laboratory; unlabelled or incorrectly labelled
An interpretation of results will be provided on the report.