Home › Biomarkers › Insulin, fasting
Insulin, fasting shows how much insulin is in your blood. Too much insulin can point to blood sugar that drops too low, and too little insulin can point to blood sugar that rises too high.[1]
On this page you can read what Insulin, fasting is, what the guidelines say about a value that is too low or too high, what affects your value and which values are best to look at alongside it.
Also known as: insulin in blood, serum insulin, total and free insulin. At the lab: INS.
Insulin is a hormone from your pancreas. Hormones are chemical messengers in your blood. They steer how certain cells or organs work.[1]
Insulin and blood sugar normally rise and fall together. After you eat, your blood sugar rises. Your pancreas then releases more insulin. Insulin helps the sugar into your cells, and when your blood sugar falls, your pancreas makes less insulin.[1]
For Insulin, fasting, the lab measures how much insulin is in your blood after you have gone a while without eating or drinking.[1]
The main reason for an insulin test is to find out what is causing low blood sugar. Very low blood sugar is serious. Your brain cells then get too little sugar, and that needs medical help straight away.[1]
The test also shows how much insulin your pancreas makes. It also helps to find a rare, benign growth in the pancreas that makes insulin, and to check whether such a growth has come back after surgery.[1]
Together with other tests, the value helps to recognise and monitor insulin resistance. Your body then responds less well to insulin, so your pancreas starts making extra insulin.[1]
Labplusarts, the lab BioProfile works with, uses a reference value for Insulin, fasting of 17.8 to 173 pmol/L, measured fasting. The lab calls a value between those limits normal.[2]
| Value | What it can mean | Who it is for |
|---|---|---|
| 17.8 to 173 pmol/L[2] | The lab calls this value normal | Measured fasting |
Reference value from Labplusarts, BioProfile's lab, for Insulin, fasting.[2]
A low value can point to your pancreas making too little insulin. Sugar then gets into your cells less well and builds up in your blood. Blood sugar that stays too high for a long time can, over time, lead to a lasting metabolic condition with serious effects on your eyes, your heart and other parts of your body.[1]
A high value can point to too much insulin in your blood. Your blood sugar can then drop too low, with symptoms such as sweating, shaking, dizziness, headache and hunger. A high value can also point to insulin resistance, where your pancreas makes extra insulin because your cells respond to it less well.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
After you eat, your blood sugar rises and your pancreas makes more insulin. That is why you usually need to go 8 to 12 hours without eating or drinking before the test.[1]
Do you take biotin (vitamin B7) or a supplement that contains biotin? Then stop taking it at least a day before the test.[1]
If you take insulin as a medicine, your body can make antibodies against insulin. These can interfere with the test and give an incorrect result. Tell your healthcare provider which insulin medicines you use, but never stop a medicine without talking to them first.[1]
Insulin, fasting is included in BioProfile 121 and 150.[3]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
