Type 1 Glossary

The Language of Type 1 Diabetes

Our T1Dictionary helps guide you through the language of Type 1 Diabetes. Either enter a word in the search or scroll down for the full list.

A protein that is part of your immune system. Antibodies are made to help destroy antigens – substances that trigger an immune response.  Each antibody is specific to one antigen.

A type of antibody (immune marker) that mistakenly targets a person’s own body, rather than an infection. If islet autoantibodies are present in a person’s blood, they have a high risk of developing T1D.

A condition where your immune system, which normally keeps your body safe against disease, attacks healthy parts of the body by mistake. Examples of autoimmune conditions are type 1 diabetes, multiple sclerosis and rheumatoid arthritis.

Immune responses against a person’s own healthy cells and tissues, that can lead to autoimmune conditions like type 1 diabetes. In T1D, the autoimmune response targets the insulin-producing beta cells of the pancreas.
Basal insulin (also known as background insulin) keeps blood-sugar levels stable during periods of fasting, such as between meals or during sleep. It plays a vital role in managing type 1 diabetes.

A type of cell that makes insulin. Beta cells are located within the islets of the pancreas. In type 1 diabetes, beta cells are targeted and destroyed by the immune system.

Also known as blood sugar, this refers to the glucose present in your blood. This glucose mainly comes from things that you eat or drink, and needs to be broken down by insulin to supply your body with energy.
A measurement of the amount of glucose in your bloodstream at a given time. After people eat, their blood glucose levels increase. Maintaining blood glucose levels within a particular range is a key goal of T1D management.
This is a way of working out the concentration of glucose (sugar) in your blood. Knowing your blood-sugar levels and acting accordingly – such as by adjusting insulin levels or eating carbohydrates – is crucial to managing type 1 diabetes.
People with type 1 diabetes take an extra amount of insulin, often with a meal or snack, to cover an expected rise in blood sugar — this is called a bolus.
A term sometimes used to describe type 1 diabetes that is characterised by wide variations or “swings” in blood sugar levels. In brittle diabetes, blood sugar levels can go from too high (hyperglycemia) to too low (hypoglycemia) very quickly.
People with type 1 diabetes must count each carbohydrate gram they eat or drink. Based on that count, they dose insulin using an “insulin-to-carb” ratio, which helps maintain stable blood-sugar levels after eating.
Closed-loop systems are an automated way of delivering insulin. They consist of a continuous glucose monitor (CGM) connected to an insulin pump. The CGM feeds real-time information about changing blood glucose levels into a special mathematical formula which calculates the precise amount of insulin required, and instructs the insulin pump to deliver the insulin.
A wearable device that continuously tracks blood sugar levels, day and night, allowing users to see patterns and trends. CGM units sound an alarm if blood sugar levels are changing rapidly, helping people avoid hypoglycaemia.
When someone becomes frustrated with the stress or demands of the disease and may feel less motivated to manage their condition. Many people with T1D experience diabetes burnout at some point.
This is the scientific name for the group of conditions commonly referred to as diabetes. This includes type 1 diabetes, type 2 diabetes, gestational diabetes, and rare forms of diabetes like LADA, MODY and neonatal diabetes.
A complication of type 1 diabetes that occurs when ketones build up in the blood. This can happen when a person’s blood sugar is too high for too long, and can be life threatening.

A doctor who specialises in conditions caused by problems with hormones, including type 1 diabetes.

A form of diabetes that develops during pregnancy. Gestational diabetes is different to both type 1 and type 2 diabetes, and usually disappears after a woman has given birth.
A hormone produced in the pancreas that raises blood sugar levels to ensure they don’t drop too low. In type 1 diabetes, glucagon doesn’t work as it should, meaning people with T1D are at risk of hypoglycemia.
Also known as smart insulin, this is a new form of insulin at an early stage of research that could “turn on” when it is needed in the body. GRI could respond to a rise in blood glucose after a meal and release insulin, then “turn off” when blood glucose levels stabilise.
HbA1c is a form of haemoglobin – a protein found in red blood cells – that is chemically linked to a sugar, usually glucose. Measuring HbA1c gives an idea of average blood glucose levels over a period of three months – the life span of a red blood cell.
A period of time following T1D diagnosis when the pancreas is still able to produce some insulin. Some people find that they only need minimal amounts of insulin during this time to keep their blood sugar levels within the target range.

Also known as high blood sugar, hyperglycemia means there is too much glucose circulating in the blood. People with T1D might experience hyperglycemia (or a “hyper” for short) if they haven’t taken enough insulin to match the carbohydrates they have eaten, or they are unwell.

Low blood sugar, usually below 4mmol/L. Also known as a hypo, it can be caused by taking too much insulin, not eating enough carbohydrates, or strenuous exercise. It’s important to treat a hypo quickly to stop blood sugar levels from falling even lower.
Sometimes, people cannot tell when their blood sugar is too low because the early warning signs aren’t triggered. This is called hypoglycemia unawareness.
Immunosuppressive drugs stop or restrict the body’s immune system. In type 1 diabetes, immunosuppressants are used following an islet transplantation, to stop the body rejecting the new beta cells.
A hormone produced in the pancreas that regulates the amount of glucose in the blood. Insulin is the only current therapy for treating T1D, and can be basal (slow-acting) or bolus (fast-acting).
A small electronic device that administers insulin via a tiny tube under the skin. Users can set the device to give a steady input of insulin throughout the day and extra (bolus) doses of insulin at meals, or other times when blood sugar is too high. See Insulin Pump Program for more details on available subsidies.
Islets are clusters of cells in the pancreas that produce hormones, including insulin. Beta cells are one of the types of cell that make up an islet.
Ketones are acids that build up in the blood and urine. When the body doesn’t have enough insulin to convert sugar into energy, it starts burning fat and body tissue instead – producing ketones. When the level of ketones in the body gets too high, this can cause diabetic ketoacidosis (DKA).
MODY – Maturity Onset Diabetes of the Young – is a rare form of diabetes that runs in families and is different from both type 1 and type 2 diabetes. There are several different types of MODY, each caused by changes in a different gene. MODY is typically diagnosed before the age of 30, but can occur at any age.
A rare form of diabetes that develops in babies under 6 months old. Neonatal diabetes is caused by a change in a gene, and is not an autoimmune condition like type 1 diabetes. Neonatal diabetes can be either transient (disappearing within the first 12 weeks of life) or lifelong.
Excessive thirst. Polydipsia is often one of the first signs of type 1 diabetes, as high blood sugar levels can make people feel extremely thirsty.
Excessive hunger or appetite. This can sometimes be a symptom of type 1 diabetes, along with polydipsia and polyuria.
Polyuria occurs when your body urinates more frequently—and often in larger amounts—than usual. It can be a symptom of type 1 diabetes. Normally, when your kidneys create urine, they reabsorb all of the sugar and direct it back to the bloodstream. In T1D, excess sugar ends up in the urine, where it pulls more water and results in more urine.
Rapid-acting insulin (also known as fast-acting, or mealtime insulin) is a form of insulin that starts working quickly after it is injected. It is usually taken before a meal, snack or drink containing carbohydrates, as directed by a healthcare professional, to regulate the rise in blood sugar which follows eating.
See Glucose Responsive Insulin.
Type 1 diabetes (T1D) is an autoimmune disease in which insulin-producing beta cells in the pancreas are mistakenly destroyed by the body’s immune system. Without insulin, sugar builds up in the bloodstream as the body is unable to process it. People with T1D must replace the insulin their body doesn’t produce — either through injections or a pump.
Also known as latent autoimmune diabetes in adults (LADA), this is a form of type 1 diabetes that also has things in common with type 2 diabetes (T2D). Type 1.5 diabetes is an autoimmune disease that is not treatable with diet or lifestyle changes, but is diagnosed during adulthood and often has a slow onset. Many people with LADA are initially misdiagnosed as having T2D.
Type 2 diabetes (T2D) is the most common type of diabetes, but is very different to T1D. It is often diagnosed later in life, and is caused by a combination of genetics and lifestyle factors. In T2D, a person’s body still produces insulin, but is unable to use it effectively. T2D can often be managed with diet or exercise changes, but more serious cases may require insulin therapy.