Primus Pathology Laboratory

Insulin Test

Last Updated on July 28, 2022 by Dr. Neeraj Gujar

Overview of Insulin Test

This test measures insulin levels in the blood. Insulin is a hormone that helps move sugar (also known as glucose) from your bloodstream to your cells. You get glucose from the foods and drinks you eat. It is the main source of energy for your body.

Insulin is crucial in maintaining glucose levels at the correct levels. It can lead to serious health problems if glucose levels become too high or low. Glucose levels that aren’t normal are known as:

  • Hyperglycemia is a high blood sugar level. This happens when your body doesn’t produce enough insulin. Insufficient insulin means that glucose cannot reach your cells. Instead, it stays in your bloodstream.
  • Hypoglycemia is a condition in which blood glucose levels are too low. Your body will release too much insulin into your bloodstream, which can lead to too much glucose in your cells. This causes less glucose to enter the bloodstream.

The most common reason for abnormal glucose levels is diabetes. The two types of diabetes that exist are –

  • Type1 Diabetes. Type 1 diabetes means that your body produces very little insulin or none at all resulting in hyperglycemia.
  • Type2 Diabetes. Type 2 diabetes is a condition in which your body can still make insulin but your cells aren’t able to absorb enough glucose from your blood. This is called insulin resistance.

Type 2 diabetes is often preceded by insulin resistance. Insulin resistance is a condition in which insulin production increases to compensate for insulin that is not working. Hypoglycemia can be caused by excess insulin in the bloodstream. Insulin resistance can get worse over time. It eventually reduces the body’s ability to make insulin. As insulin levels drop, blood sugar levels rise. Type 2 diabetes can occur if insulin levels do not return to normal.

Other names for this test include fasting insulin, insulin serum, and total and free insulin.

Also Read: Important Medical Tests for People Above 50

Why Test Is Done?

A blood test for insulin is most commonly used to:

  • Learn the causes of hypoglycemia (low sugar levels)
  • Check the health of those with type 2 diabetes
  • Diagnosis and monitor insulin resistance
  • Determine if you have an insulinoma, a type or tumor that has developed on the Pancreas. The test can be used to determine if the tumor has been removed.

Sometimes, an insulin test can be used with other tests to diagnose and monitor type 1. Other tests include hemoglobin A1C and glucose testing.

women injecting herself with an insulin shot


When To Get Tested?

If you experience hypoglycemia (low sugar), an insulin blood test may be necessary. The symptoms include:

  • Sweating
  • Trembling
  • Extreme hunger
  • Irregular heartbeat
  • Dizziness
  • Confusion
  • Blurred vision

This test may be required if your results point towards low blood sugar in other tests.

How To Get Tested?

You will be needed to observe fasting for at least eight hours before the test.

Also Read: What does a Fasting Before Sugar (FBS) Test Result Mean?

During the Test

A small needle is used by a health professional to take blood from a vein on your arm. Once the needle has been inserted, some blood will be taken and stored in a vial or test tube. The needle may cause a slight stinging sensation when it is inserted or removed.

After The Test

A blood test is not a risky procedure. Although you may feel a little bit of pain or bruise around the site where the needle was inserted, most symptoms disappear quickly.

Test Results

If your insulin levels are too high, it may indicate–

  • Type 2 diabetes
  • Insulin resistance
  • Hypoglycemia
  • Cushing’s syndrome is a disorder caused by the adrenal cells. The hormones produced by the adrenal glands help to break down fat and proteins.
  • A pancreatic tumor called insulinoma

If your insulin levels are too low, it may indicate–

  • Hyperglycemia (high blood glucose)
  • Type 1 Diabetes
  • Pancreatitis is an inflammation of the pancreas.

Talk to your doctor if you have any questions about your results.

Also Read: Diagnosis of Diabetes with HbA1c Test & Treatment Options Available


Why is insulin needed to be injected?

Insulin can only be given by injection or via an insulin pump. Insulin cannot be administered orally as it is a protein that must be broken down in the stomach.

How can an insulinoma be treated?

Insulinomas, which are insulin-producing tumors, are generally benign. They can be treated by being found and removed. They generally do not return once they are removed.

What is an insulin tolerance test?

Although not commonly used, the insulin tolerance test (ITT), is one way to determine insulin sensitivity or resistance. It is especially useful for obese people and people with PCOS. This test requires an IV infusion with insulin and subsequent measurement of glucose levels.


by Dr. Neeraj Gujar

Dr. Neeraj Gujar has done his M.D. in Pathology from Government Medical College. He has worked at various organisations such as Breach Candy Hospital and Tata Memorial Hospital along with many other private organisations. During his working career, he realised the pressing need for exceptional quality diagnostic services. A diagnostic centre that can consistently give accurate results verified by a consultant doctor (M.D. Pathologist) on which your doctor can depend. This has been the founding principle of Primus Pathology and Diagnostics.

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