Insulin

Clinical Chemistry

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Description

Insulin is a hormone formed from a precursor, proinsulin, in pancreatic beta-cells. Insulin is released in response to a rise in glucose and functions include facilitation of glucose uptake by cells in the liver, adipose tissue and muscles.

Causes of raised insulin with hypoglycaemia include insulinoma, use of oral hypoglycaemic drugs e.g. sulphonylureas, persistent hyperinsulinaemic hypoglycaemia of infancy, infants of diabetic mothers and Beckwith syndrome. Hyperinsulinism without hypoglycaemia may be seen in insulin resistance.

Causes of low insulin include type 1 diabetes and advanced type 2 diabetes. Additionally, low insulin is an expected finding in hypoglycaemia or the fasting state.

Please note that most types of exogenous insulin are not detected by the Roche insulin assay.

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Indications

Investigation of hypoglycaemia.

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Sample Type

SST/Gel, minimum 2 mL (1 mL separated serum), or Lithium-heparin plasma (green-top). Fluoride/oxalate specimen required for glucose measurement.

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 1 day

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Testing Frequency

Daily

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External Notes

Haemolysed samples give spuriously low insulin results.

Long-term storage - 6 months at -20C. Freeze only once. (Source: Roche)

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.