Glossary of Diabetes Terminology

Here are definitions of key terms related to diabetes, designed to help individuals better navigate their care, research, and daily management.
A1C (HbA1c)
A blood test that shows the average level of blood glucose over the past 2–3 months. Used to diagnose and monitor diabetes.
Alpha Cells
Cells in the pancreas that produce glucagon, a hormone that raises blood glucose levels.
Autoimmune Disease
A condition in which the body’s immune system attacks its own cells; Type 1 diabetes is an autoimmune disease.
Basal Insulin
Long-acting insulin that helps control blood glucose levels throughout the day and night, even when not eating.
Beta Cells
Cells in the pancreas that produce insulin.
Blood Glucose (Blood Sugar)
The main sugar found in the blood. It’s the body's main source of energy and comes from food.
Bolus Insulin
Short-acting insulin taken at mealtime to control spikes in blood glucose.
Carbohydrate Counting
A method of managing blood sugar by tracking the number of carbohydrates consumed.
Continuous Glucose Monitor (CGM)
A device that tracks glucose levels throughout the day and night via a small sensor under the skin.
Diabetic Ketoacidosis (DKA)
A serious complication of diabetes where the body breaks down fat too quickly, producing ketones and leading to a dangerous acid buildup.
Fasting Blood Glucose
The level of glucose in the blood after not eating for at least 8 hours. Used to help diagnose diabetes.
Gestational Diabetes
A type of diabetes that develops during pregnancy and usually resolves after childbirth.
Glucagon
A hormone made by the pancreas that raises blood glucose levels by signaling the liver to release stored sugar.
Glucose Tolerance Test (GTT)
A test to assess how the body processes glucose, often used in diagnosing gestational or Type 2 diabetes.
Glycemic Index (GI)
A ranking of carbohydrates on a scale from 0 to 100 based on how quickly they raise blood sugar levels.
Hemoglobin A1C
See A1C.
Hyperglycemia
High blood glucose levels (typically >180 mg/dL after eating).
Hypoglycemia
Low blood glucose levels (typically <70 mg/dL). Can cause shakiness, confusion, and in severe cases, unconsciousness.
Insulin
A hormone produced by the pancreas that allows glucose to enter cells to be used for energy.
Insulin Resistance
A condition where the body’s cells do not respond properly to insulin. Common in Type 2 diabetes.
Islets of Langerhans
Clusters of cells in the pancreas that contain beta and alpha cells responsible for producing insulin and glucagon.
Ketones
Acids made when the body breaks down fat for energy. High levels can be dangerous and lead to diabetic ketoacidosis (DKA).
Neuropathy
Nerve damage often caused by chronic high blood sugar, leading to numbness, pain, or weakness, especially in the hands and feet.
Oral Glucose Tolerance Test (OGTT)
A test in which blood glucose levels are measured after consuming a sugary drink. Used to diagnose diabetes and prediabetes.
Pancreas
An organ that produces insulin and glucagon to help regulate blood glucose levels.
Prediabetes
A condition where blood glucose levels are higher than normal but not high enough for a diabetes diagnosis.
Retinopathy
Damage to the blood vessels in the retina caused by chronic high blood sugar, which can lead to vision problems.
Type 1 Diabetes
An autoimmune disease where the immune system destroys insulin-producing beta cells in the pancreas.
Type 2 Diabetes
A chronic condition where the body does not use insulin properly (insulin resistance), often coupled with insulin deficiency.
Units of Insulin
The measure used to quantify insulin dosage.
Urine Ketone Test
A test used to check for ketones in the urine, which may indicate insufficient insulin.