Insulin, 1.5 Hours Post Glucose, Serum or Plasma, Mass Concentration

What the Test Measures

Insulin is a hormone made by the pancreas that helps move glucose (sugar) from your blood into your cells for energy. This test measures the concentration of insulin in a blood sample collected about 90 minutes (1.5 hours) after you drink a glucose solution. It is part of a stimulated or dynamic testing approach that evaluates how your body reacts to a sugar challenge rather than measuring insulin only while you are fasting.

Why Your Doctor May Order It

Your clinician may order this test when you have signs of insulin resistance, such as high blood sugar, excess weight around the abdomen, or difficulty losing weight. It can also be used when evaluating conditions in which the body makes too much or too little insulin, and to help identify problems such as low blood sugar (hypoglycemia) caused by excess insulin. The stimulated value is often interpreted together with fasting glucose and fasting insulin results.

How the Test Is Performed

You typically have a baseline blood draw, then drink a glucose-containing beverage, and a second blood sample is taken about 1.5 hours later. The blood may be collected into a serum or plasma tube and measured using an immunoassay method. Your care team will give you specific instructions about whether you need to fast beforehand and how long the appointment will take.

How to Prepare and What to Expect

Preparation depends on your clinician's instructions, so follow them carefully. You may be asked to avoid eating for a period before the test and to avoid strenuous activity right before it. Tell your care team about all medicines and supplements you take, because some can affect insulin levels. The test involves standard needle sticks, and most people tolerate it with only mild, brief discomfort. Because this measurement is tied to a timed glucose challenge, results should be interpreted as part of your overall clinical picture.