Fasting insulin test, is used to help evaluate insulin production 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.
Results Reference:
| Disorder | Fasting insulin level | Fasting glucose level |
| none | normal | normal |
| insulin resistance | high | normal or somewhat elevated |
| not enough insulin produced by the beta cells (may be seen in insulinomas, Cushing syndrome, excess administration of exogenous insulin, etc.) | normal, or high | low |
What else can I know from the test results?
- Elevated insulin levels are seen with: acromegaly, Cushing syndrome, use of drugs such as corticosteroids, levodopa, oral contraceptives, fructose or galactose intolerance, insulinomas, obesity, insulin resistance (often appearing in type 2 diabetes), acanthosis nigricans, and metabolic syndrome.
- Decreased insulin levels are seen with: diabetes, hypopituitarism, pancreatic diseases such as chronic pancreatitis (including cystic fibrosis) and pancreatic cancer.
Keywords: Fasting Insulin, Insulin, Insulin serum
