Fasting Insulin Test
A blood test that measures insulin, a hormone made by the pancreas that moves glucose (sugar) from your blood into your cells.
Fasting Insulin Test
A blood test that measures insulin, a hormone made by the pancreas that moves glucose (sugar) from your blood into your cells.
Also known as
- Insulin (fasting)
- Insulin in blood
What it measures
- Insulin level in the blood
Why a doctor may order it
It is mainly used to help find the cause of low blood glucose (hypoglycemia). With other tests, it may also be used to look into insulin resistance or to guide treatment decisions in type 2 diabetes.
What it helps evaluate
It can help a doctor understand how much insulin your pancreas is making alongside your blood glucose results. It is not a routine test for everyone — it is ordered when a doctor needs to answer a specific question.
Preparation
You will probably need to fast for 8 to 12 hours. If you take biotin (vitamin B7) supplements you may need to stop them for at least a day before the test, but do not stop any medicine unless your doctor tells you to.
Fasting
Fasting for about 8 to 12 hours is usually needed. Follow the instructions you are given.
Important considerations
- Biotin supplements can affect some results — tell the lab about any supplements you take.
Discuss results with your doctor
Symptoms of very low blood glucose (fainting, confusion, seizures) need urgent medical help. Otherwise talk to a doctor about your symptoms and results.