Insulin is a hormone produced by the pancreas that regulates blood glucose levels.

The fasting test reflects baseline insulin secretion without food intake influence.

Clinical uses include:

Assessing insulin resistance (often combined with fasting glucose to calculate HOMA‑IR).

Evaluating beta‑cell function in diabetes.

Investigating hypoglycemia causes.

Monitoring patients with metabolic syndrome, obesity, or polycystic ovary syndrome (PCOS).

Performed after overnight fasting (8–12 hours).

Analyte: Serum insulin concentration (µIU/mL).

Normal Range (varies by lab): ~2–25 µIU/mL (fasting).

Abnormal Findings:

High fasting insulin: Suggests insulin resistance, metabolic syndrome, or early type 2 diabetes.

Low fasting insulin: Indicates type 1 diabetes, pancreatic insufficiency, or hypoglycemia due to non‑insulin causes.

Clinical Use:

Provides a direct measure of pancreatic insulin secretion.

Helps guide diagnosis and management of diabetes and metabolic disorders.

Supports risk assessment for cardiovascular disease linked to insulin resistance.