In brief
Measures insulin in the blood. It is most often used to investigate low blood glucose, usually together with C-peptide.
What it measures
The level of insulin, the pancreas hormone that lets glucose enter cells, and often C-peptide, a by-product made when the pancreas makes insulin. C-peptide is a more accurate measure of how much insulin your pancreas is making.
Why it is done
Mostly to investigate the cause of low blood glucose. Pathology Tests Explained notes that C-peptide can also be used to diagnose insulin resistance.
Reading the results
- Glucose, insulin and C-peptide measured together are sometimes used to diagnose low blood glucose (hypoglycaemia).
- These tests can tell insulin made by your body apart from insulin that has been injected.
- A result flagged as high or low does not necessarily mean that anything is wrong.
Before the test
A fasting sample is required.
What can affect the result
- Recent food
- Some medicines
- Injected insulin
Related topics
Sources
Test information summarised from the sources listed on this page, read on 19 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.