Insulin in Blood

Insulin in the Blood: Why It’s Important

Insulin is an important hormone in the body that helps with the processing of sugar in the bloodstream, and therefore, is very important in maintaining healthy levels of blood sugar. Without insulin, the body’s cells cannot properly use sugars, leading to a number of potentially severe health issues such as high blood sugar, diabetes, and heart disease. Measuring insulin levels in the blood can provide a snapshot of a person’s overall health and offer insight into the effectiveness of certain treatments.

What Is the Test?

The insulin in blood test measures the amount of insulin in a person’s blood. These tests are often used to diagnose diabetes and can be used to monitor insulin levels in those with diabetes who take insulin or oral medications.


A person will need to fast for 8-12 hours before an insulin blood test. They may also need to stop taking any insulin or diabetes medications prior to the test, so always consult with a doctor prior to the test. The doctor will provide instructions as to what food and medications can be taken prior to the test.


The insulin blood test is relatively simple. A doctor or nurse will take a sample of the person’s blood, typically from the arm, with a needle. The lab tech will then measure the insulin level in the blood with a machine.

Types of Tests

There are several different types of insulin tests that can be done. They include:

  • Fasting Insulin: Measures levels of insulin after the person has not eaten for 8-12 hours.
  • Oral Glucose Tolerance Test: Measures levels post-eating.
  • Postprandial Insulin: Measures levels after two hours post-meal.
  • Random Blood Insulin: Measures levels without a fasting period.


The insulin blood test carries minimal risks. There may be slight bruising or pain at the glucose test site, but this will subside quickly. There is also the risk of infection, but this risk can be reduced significantly with proper disinfection.

When is the insulin test used?

Insulin tests are primarily used to diagnose diabetes. A doctor may order the insulin test to monitor the effectiveness of treatment for patients with type 1 or type 2 diabetes. An insulin test may also be used to diagnose hypoglycemia, a condition in which there are abnormally low levels of sugar in the bloodstream. Insulin tests are also sometimes used to monitor liver function.


Insulin tests measure the amount of insulin in a person’s bloodstream. These tests are primarily used to diagnose diabetes, hypoglycemia, and monitor the effectiveness of treatment for those with diabetes. They are relatively easy and virtually painless, carrying very few risks.