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Insulin

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Also known as: Fasting Insulin
Formal name: Insulin, serum
Related tests: C-peptide, Glucose Tests

At a Glance

Why Get Tested?

To help evaluate insulin production by the beta cells in the pancreas; to help diagnose the presence of an insulin-producing tumor in the islet cells of the pancreas (insulinoma); to help determine the cause of low blood glucose (hypoglycemia); to help identify insulin resistance, or to help determine when a type 2 diabetic might need to start taking insulin to supplement oral medications

When to Get Tested?

When you have low blood glucose levels with symptoms such as sweating, palpitations, dizziness, fainting; when you have diabetes and your health practitioner wants to monitor your insulin production; sometimes when it is suspected that you have insulin resistance

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

You may be asked to fast for 8 hours before the blood sample is collected, but occasionally a health practitioner may do the test with, for example, a glucose tolerance test. In some cases, a health practitioner may request that you fast longer.