Insulin, Serum (Quantitative)

What Is Insulin?

Insulin is a critical hormone that helps your body manage blood sugar (glucose). It’s produced by cells in your pancreas called beta cells. When your blood sugar rises after eating, insulin signals your body to take glucose from the blood and store it for energy or use it immediately. Too little insulin can lead to high blood sugar, while too much can cause low blood sugar (hypoglycemia).

Why Might You Need This Test?

Your doctor may order an insulin test to diagnose or monitor conditions like diabetes, insulinoma (a rare tumor that causes excessive insulin production), or to check for insulin resistance. It may also be used in research or specialized clinical scenarios where precise insulin levels are important, such as evaluating metabolic responses to medications or treatments for metabolic disorders.

How Is This Test Done?

For this test, a blood sample is drawn from a vein, usually in your arm. The blood is collected in a tube and sent to a lab where it is processed to separate serum (the liquid part after clotting). The insulin level is then measured using an immunoassay method, which detects the hormone’s presence with high sensitivity.

What Do Results Mean?

Results are typically reported as a mass concentration (e.g., micrograms per liter). While reference ranges can vary by lab, very low levels may suggest insulin deficiency, while very high levels could indicate conditions like insulinoma or reactive insulin spikes after meals. Your doctor will interpret results in the context of your overall health and symptoms.