Five Hour Insulin Resistance Test

What is this test?

We will sample your blood at a fasting baseline and then having you drink a metered amount of glucose. We will then sample your blood at timed intervals over a period of 5 hours.  Each sample is tested for insulin levels as your body reacts to the metered intake of glucose.  Results give a trend that will be used by your physician to identify if you have insulin resistance. 

What preparation is necessary?

You cannot eat or drink (NPO) from midnight the night before test so drink plenty of water (water only) up to midnight.  You will remain NPO throughout the 5 hours after the first blood sample is taken except to drink a metered amount of liquid glucose.  30 minutes after the drink we take a blood sample and then again every 60 minutes over a 5 hour period.  Expect to be in office for 6 hours to complete this test.  You must remain NPO until the last sample is drawn.

Why are looking at insulin levels?

The fundamental pathology in developing type 2 diabetes mellitus is insulin resistance. Current treatments target the disease only after it has manifested symptoms.  But if we seek to identify early insulin resistance then there is a great opportunity for prevention.  The purpose of this test is to identify insulin resistance early when there are still many options to prevent type 2 diabetes.  Insulin resistance means that the insulin molecule cannot act upon the insulin receptors in the body because the receptors have become insensitive.  Therefore, it takes a lot of insulin production by the pancreas to stimulate the insulin receptors and thereby reduce the blood glucose to normal.  In many patients, the blood sugar levels are kept in range at the expense of very high insulin levels.  High levels of insulin production by the pancreas will eventually lead to pancreatic endocrine failure, which then leads to dependence on insulin injections.


Early intervention and prevention of type 2 diabetes due to insulin resistance.  Caught early, insulin resistance can be reversed and developing type 2 diabetes avoided.