Glossary

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A1C test
Also referred to as a hemoglobin A1C, H1bA1c, or glycohemoglobin test. This test measures the percentage of hemoglobin in red blood cells that has been glycated, or sugarized, over the last two to three months. The average life cycle of a red blood cell is 100 to 120 days, so measuring how glycated the hemoglobin in red blood cells is, can give an accurate picture of average blood glucose levels over time. Higher blood glucose levels will result in a higher percentage of hemoglobin with sugar attached. Generally, an A1C level below 5.7 percent is considered normal. An A1C between 5.7 and 6.4 percent usually indicates prediabetes, and an A1C of 6.5 percent or higher indicates diabetes. However, there’s no one-size-fits-all A1C target, and patients should discuss an appropriate target for them with their providers.
Acetone
A chemical formed in the blood when the body uses fat instead of glucose (sugar) for energy. If acetone forms, it usually means the cells do not have enough insulin, or cannot use the insulin that is in the blood, to use glucose for energy. Acetone passes through the body into the urine.
Acidosis
Too much acid in the body. For a person with diabetes, this can lead to ketoacidosis.
Acute
Abrupt onset that is usually severe; happens for a limited period of time.
Adenovirus
Responsible for respiratory illness that can cause cold like symptoms, sore throat, bronchitis, pneumonia, diarrhea, and pink eye.
Adult-onset diabetes
Former term for type 2 diabetes, also formerly called noninsulin-dependent diabetes.
Advanced glycosylation end (AGE) products
Glycated, or sugarized, proteins and lipids that can lead to damage of nerves and blood vessels throughout the body.
Albuminuria
More than normal amounts of a protein called albumin in the urine. Albuminuria may be a sign of kidney disease, a problem that can occur in people who have had diabetes for a long time.
Alpha cell
A type of cell in the islets in the pancreas. Alpha cells make and release a hormone called glucagon, which stimulates the liver to release glucose into the bloodstream.
Amino acids
The building blocks of proteins; the main material of the body’s cells. Insulin is made of 51 amino acids joined together.
Amyotrophy
A disease of diabetic neuropathy that causes muscle weakness and wasting.
Antibodies
Proteins that the body produces to protect itself from foreign substances (such as bacteria or viruses).
Antidiabetic agent
A substance that helps a person with diabetes manage the level of glucose in the blood so the body functions properly. (See also insulin, oral diabetes medication).
Antigens
Substances that cause an immune response in the body. The body produces antibodies to fight antigens, or harmful substances, and try to eliminate them.
Anti-insulin antibody test
The anti-insulin antibody test checks to see if your body has produced antibodies against insulin.
Artery
A large blood vessel that carries blood from the heart to other parts of the body. Arteries are thicker than veins and have stronger, more elastic walls.
Artificial pancreas
A large machine used in hospitals that constantly measures glucose in the blood and releases the right amount of insulin in response. Studies are being conducted to develop a smaller version of this machine that could be implanted in the body to function as a real pancreas.
Atherosclerosis
A disease of the arteries in the heart that occurs when the normal lining of the arteries deteriorates, the walls of the arteries thicken, and deposits of fat and plaque block the flow of blood through the arteries. The arteries that supply blood to the heart become severely narrowed, decreasing the supply of oxygen-rich blood to the heart especially during times of increased activity.
Autoantibodies
A type of antibody produced by the immune system that is directed against the individual’s own proteins. Autoantibodies are the cause of many autoimmune diseases.
Autoimmune disease
Disorder of the body’s immune system in which the immune system mistakes your body’s own cells as invaders and attacks them.
Autonomic neuropathy
Nerve damage most often affecting the digestive system, blood vessels, urinary system, and sex organs. Autonomic nerves are not under a person’s control and function on their own.
Background retinopathy
Also called nonproliferative retinopathy. Is the early stage of diabetic retinopathy that does not usually impair vision.
Basal rate
Continuous supply of low levels of insulin, such as provided by the insulin pump.
Beta cell
A type of cell in the islets in the pancreas. Beta cells make and release insulin, which helps the body’s cells to absorb glucose from the bloodstream.
Biguanides
A class of medication that tells the liver to decrease its production of glucose, which lowers glucose levels in the bloodstream.
Biosynthetic insulin
A man-made insulin much like human insulin.
Blood glucose (blood sugar)
See: Glucose
Blood glucose (sugar) testing
A method of testing how much glucose (sugar) is in your blood. Blood glucose testing involves pricking your finger with a lancing device, putting a drop of blood on a test strip, and inserting the test strip into a blood glucose testing meter that displays your blood glucose level.
Blood pressure
The measurement of the pressure or force inside the blood vessels (arteries) with each beat of the heart. Blood pressure is written as two numbers; the first number, the systolic pressure, is the pressure in the arteries when the heart beats and fills the arteries with blood. The second number, the diastolic pressure, is the pressure in the arteries when the heart rests between beats.
Brittle diabetes
When a person’s blood glucose level often shifts very quickly from high to low and from low to high. Also called labile diabetes and unstable diabetes.
Blood urea nitrogen (BUN)
Waste product of the kidneys. Increased BUN levels may indicate early kidney damage.
Bunion
A bump or bulge on the first joint of the big toe caused by the swelling of a sac of fluid under the skin. Shoes that fit well can prevent bunions from forming. Bunions may lead to other problems, such as serious infection.
Callus
A small area of skin, usually on the foot, that has become thick and hard from rubbing or pressure. Calluses may lead to other problems, such as serious infection. Shoes that fit well can prevent calluses from forming.
Calorie
Energy that comes from food. Some foods have more calories than others. Fats have many calories. Most vegetables have few. People with diabetes are advised to follow meal plans with suggested amounts of calories for each meal and/or snack.
Carbohydrate
One of the three main classes of foods and a source of energy. Carbohydrates are mainly sugars and starches that the body breaks down into glucose (a simple sugar that the body can use to fuel its cells).
Cardiologist
A doctor who takes care of people with heart disease; a heart specialist.
Cardiovascular
Relating to the heart and blood vessels (arteries, veins, and capillaries).
Cerebral vascular disease
A type of cardiovascular disease that occurs when the blood vessels that flow to the brain become narrowed, blocked, or hardened. This disease can lead to transient ischemic attacks (TIAs) and stroke.
Certified diabetes educator (CDE)
A healthcare professional who is certified by the American Association of Diabetes Educators to teach people with diabetes how to manage their condition.
Cholesterol
A waxy, odorless substance made by the liver that is an essential part of cell walls and nerves. Cholesterol plays an important role in body functions such as digestion and hormone production. In addition to being produced by the body, cholesterol comes from animal foods that we eat. Too much cholesterol may cause a build-up in the artery walls and lead to atherosclerosis.
Claudication
See: Intermittent claudication
Coma
A severe emergency in which a person is not conscious because his or her blood glucose (sugar) is too high or too low.
Coronary artery disease (CAD)
A heart condition caused by the hardening or thickening of blood vessels that flow to and from the heart.
Coxsackievirus B
Important human pathogens that cause both acute and chronic diseases.
Cytomegalovirus (CMV)
A virus spread by close contact with body fluids. CMV is related to the viruses that cause chickenpox and mononucleosis.
Dawn phenomenon
A sudden rise in blood glucose levels in the early morning hours. It is much more pronounced in patients with type 2 diabetes. It is caused by the “normal” circadian release of cortisol (a hormone that stimulates glucose release from the liver) in the morning.
Dehydration
Great loss of body water. If a person with diabetes has a very high blood glucose level, it causes increased water loss, and the person becomes very thirsty.
Dextrose
See: Glucose
Diabetes (Diabetes mellitus)
See: Type 1 diabetes and Type 2 diabetes
Diabetic coma
Loss of consciousness caused by extremely high blood glucose levels.
Diabetic neuropathy
Nerve damage that results from diabetes.
Diabetic ketoacidosis (DKA)
Severe, untreated hyperglycemia (high blood glucose) that needs emergency treatment. DKA happens when the body doesn’t have enough insulin and starts using fat for energy. Ketoacidosis can lead to coma and even death.
Dietician
An expert in nutrition who helps people plan the type and amount of foods to eat for special health needs. A registered dietician (RD) has special qualifications.

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Emergency medical identification
Cards, bracelets, or necklaces with a written message, used by people with diabetes or other medical problems to alert others in case of a medical emergency, such as coma.
Endocrinologist
A doctor who treats people who have problems with their endocrine glands. The pancreas is an endocrine gland.
Fasting plasma glucose test
A test used to diagnose diabetes that is easy to administer, convenient for patients, and less expensive than other tests. The FPG measures a person’s blood glucose level after fasting for at least eight hours. A fasting glucose level below 100 mg/dL is considered normal. A fasting glucose level between 100 and 125 mg/dL indicates prediabetes, and when it’s 126 mg/dL or above, it could mean diabetes. The standard diagnosis of diabetes is made when two blood tests taken on different days show that your fasting blood glucose level is greater than or equal to 126 mg/dL.
Fats
Substances that help the body use some vitamins and keep the skin healthy. They are also the major way the body stores energy. In food, there are two types of fats: saturated and unsaturated. To maintain your blood cholesterol and triglyceride (lipid) levels as near the normal ranges as possible, decrease the total amount of fat to 30% or less of your total daily calories and reduce saturated fat and cholesterol.
Flatulence
Passing gas.
Fructose
A type of sugar found in many fruits and vegetables and in honey. Fructose is used to sweeten some diet foods.
Gangrene
The death of body tissues, usually due to a lack of oxygen and nutrients from adequate blood supply.
Gastroparesis
Also called delayed gastric emptying. It is a disorder where the stomach takes too long to empty itself as a result of nerve damage caused by diabetes.
Gestational diabetes
A high blood glucose level that is discovered during pregnancy. As pregnancy progresses, there is an increased need for glucose for the developing baby. Additionally, hormone changes during pregnancy affect the action of insulin, resulting in high blood glucose levels. Usually, blood glucose levels return to normal after childbirth. However, women who have had gestational diabetes are at increased risk of developing type 2 diabetes later in life.
Glaucoma
An eye disease associated with increased pressure within the eye. Glaucoma can damage the optic nerve and cause impaired vision and blindness.
Glucagon
A hormone that raises the level of glucose (sugar) in the blood by stimulating the liver to release glucose from glycogen stores. Glucagon is sometimes injected when a person has lost consciousness (passed out) from hypoglycemia (low blood glucose). The injected glucagon helps raise the level of glucose in the blood.
Glucose
A simple sugar found in the blood. It is the body’s main source of energy; also known as dextrose.
Glutamic acid decarboxylase 65 (GAD-65) test
A test that looks for glutamic acid decarboxylase 65 (GAD-65) antibodies. GAD-65 antibodies are commonly found in patients with type 1 diabetes.
Glycation
The bonding of a sugar molecule to a protein or lipid.
Glycohemoglobin test
See: A1C test.
Glycogen
Excess glucose stored in liver and muscle tissue. Glycogen in the liver can be broken down into individual glucose molecules to be used as energy when needed.
Glycosylated hemoglobin test (HbA1c)
See: A1C test.
Hemoglobin
A protein found in red blood cells responsible for carrying oxygen.
Hemoglobin variant
Mutations in hemoglobin found within a population caused by variations in genetics. Hemoglobin variants are often found in people of African, Mediterranean, and Southeast Asian descent.
High blood pressure
A condition when the blood flows through the blood vessels at a force greater than normal. High blood pressure strains the heart, harms the arteries, and increases the risk of heart attack, stroke, and kidney problems. Also called hypertension.
High blood glucose
See: Hyperglycemia
Home blood glucose monitoring
A way in which a person can test how much glucose (sugar) is in the blood. Also called self-monitoring of blood glucose.
Hormone
A chemical released by the endocrine glands and other tissues to help control certain functions in the body. For instance, insulin is a hormone made by the beta cells in the pancreas, and when released, it helps other cells to use glucose for energy.
Human insulin
Bio-engineered insulin that is very similar to insulin made by your own body. The DNA code for making human insulin is put into bacteria or yeast cells and the insulin made is purified and sold as human insulin.
Human leukocyte antigen (HLA) complex
A group of related proteins that help the body’s immune system distinguish between its own proteins and those made from foreign bacteria or viruses. HLA variants can cause an autoimmune response, where the immune system attacks the body’s own cells.
Hyperglycemia
High blood glucose that is a sign that diabetes is out of control. Many things can cause hyperglycemia. It occurs when the body does not have enough insulin or does not effectively use the insulin it does have.
Hypertension
See: High blood pressure
Hypoglycemia
Low blood glucose that occurs when there is too much insulin and not enough glucose in your body. Hypoglycemia can occur in people taking insulin or an oral diabetes medication to manage diabetes. Hypoglycemia can result from taking too much diabetes medication; missing a meal, not eating the whole meal, or eating later than usual; exercising more than usual; or consuming alcohol.
Immune system
The body's defense against infectious organisms and other foreign invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease.
Impaired glucose tolerance
Blood glucose levels between 140 and 199 mg/dL two hours after a 75 gram dose of glucose (see Oral glucose tolerance test). Blood glucose levels are higher than normal but not high enough to diagnose type 2 diabetes.
Impotence
Persistent inability of the penis to become erect or stay erect. Some men may become impotent after having diabetes for a long time because nerves and blood vessels become damaged.
Injection site rotation
Changing the areas on the body where a person injects insulin. By changing the area of injection, the injections will be easier, safer and more comfortable. If the same injection site is used over and over again, scar tissue can develop under the skin, which keeps the insulin from being used properly.
Injection sites
Places on the body where a person can inject insulin most easily.
Insulin
A hormone that helps the body use glucose for energy. The beta cells of the pancreas make insulin.
Insulin dependent diabetes
Former term used for type 1 diabetes.
Insulin mixture
A mixture of insulin that contains short- and intermediate- or long-acting insulin. You can buy premixed insulin to eliminate the need for mixing insulin from two bottles.
Insulin pump
A small, computerized device, about the size of a beeper, that is worn on a belt or put in a pocket. Insulin pumps have a small flexible tube with a fine needle on the end to insert a plastic catheter under the skin of the abdomen. The needle is removed once the catheter is taped in place. A carefully measured, steady flow of insulin is released into the tissue.
Insulin reaction
Low blood glucose (hypoglycemia) that results when a person with diabetes has injected too much insulin, eaten too little food, or has exercised without eating extra food.
Insulin receptors
Areas on the outer part of a cell that allow insulin in the blood to join or bind with the cell. When the cell and insulin bind together, the cell can take glucose from the blood and use it for energy.
Insulin resistance
When a person’s body will not allow insulin to work properly in the body, even if the person takes very high daily doses of insulin. This condition can occur when a person is overweight, and it often improves when the person loses weight.
Insulin shock
A severe condition that occurs when the level of blood glucose drops quickly.
Intermittent claudication
Pain in the muscles of the legs that occurs off and on, usually while walking or exercising. The pain results from narrowing of the blood vessels feeding the muscle. Drugs are available to treat this condition.
Islets
Clusters of cells in the pancreas that contain alpha and beta cells.

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Jet injector
A device that uses high pressure to push insulin through the skin and into the tissue.
Juvenile-onset diabetes
Former term used for type 1 diabetes.
Ketoacidosis
See: Diabetic ketoacidosis (DKA)
Ketones
The byproduct produced when the body burns fat for energy. When your blood glucose gets too high, your body breaks down its own fat and protein for energy instead of glucose. When fat is used, ketones appear in your urine and blood. A large amount of ketones in your system can lead to a serious condition called diabetic ketoacidosis.
Ketones urine test
A test that looks for the presence of ketones, a byproduct that is produced when the body resorts to using fat tissue for energy, as opposed to glucose.
Kidney disease (nephropathy)
Any one of several conditions caused by changes in the very small blood vessels in the kidneys. People who have had diabetes for a long time may develop nephropathy. Kidney disease is detected when urine test results indicate there is protein in the urine.
Kidney threshold
See: Renal threshold
Lactic acidosis
When lactic acid builds up in the bloodstream faster than it can be removed. Lactic acid is produced when oxygen levels in the body drop.
Lactose
A type of sugar found in milk and milk products.
Lancet
A fine, sharp pointed needle for pricking the skin. Used in blood glucose monitoring.
Laser treatment
The use of a strong beam of light (laser) used to preserve vision through photocoagulation (finely cauterizing damaged tissue with light). Focal laser surgery is used in diabetic macular edema to cauterize areas that are leaking fluid. Scattered photocoagulation (1200-1800 individual laser spots) is used in proliferative retinopathy to slow the growth of new abnormal blood vessels.
Late-onset diabetes
Former term used for type 2 diabetes.
Lipid
A term for a fat or fat-like substance in the blood. The body stores fat as energy for future use just like a car that has a reserve fuel tank. When the body needs energy, it can break down lipids into fatty acids and burn them like glucose.
Low blood glucose
See: Hypoglycemia
Metabolic syndrome
A group of health risks that increase the chance of developing heart disease, stroke, and diabetes. These health risks include large waist size, high levels of triglycerides, low levels of HDL (good cholesterol), high blood pressure, and high blood glucose levels. A person with three out of the five health risks will be diagnosed with metabolic syndrome.
Metabolism
All of the physical and chemical processes in the body that occur when food is broken down, energy is created, and wastes are produced.
Mg/dL (milligrams per deciliter)
Measurement that indicates the amount of glucose in a specific amount of blood.
Mixed dose (combination dose)
A prescribed dose of insulin in which two types of insulin are combined and injected at once. A mixed dose commonly combines regular insulin, which is fast-acting, with a longer-acting insulin. A mixed dose may be prescribed to provide better blood glucose control.
Mumps
A contagious disease caused by a virus. It typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite, followed by swollen salivary glands. You can protect yourself and your family against mumps with vaccination.
Nephropathy
Disease of the kidneys caused by damage to the small blood vessels or to the units in the kidneys that clean the blood. People who have had diabetes for a long time may develop nephropathy.
Neurologist
A doctor who treats people who have problems of the nervous system.
Non-insulin dependent diabetes
Former term for type 2 diabetes.
Nutritionist
See: Dietician.
Obesity
A condition when people who have too much body fat for their age, height, sex, and bone structure. Obesity is diagnosed using body mass index (BMI). A BMI of 30.0 or above is considered obese. Obesity works against the action of insulin. Extra body fat is thought to be a risk factor for diabetes.
Ophthalmologist
A doctor who treats people with eye diseases.
Optometrist
A person professionally trained to test the eyes and to detect and treat eye problems and some diseases by prescribing and adapting corrective lenses.
Oral diabetes medications
Medications in the form of tablets that people take to lower the level of glucose in the blood. Oral diabetes medications are prescribed for some people whose pancreas still produces some insulin.
Oral glucose tolerance test
A test to diagnose diabetes, although its use is no longer recommended in current clinical practice guidelines. The test is done in a lab or doctor’s office in the morning before the person has eaten. First a sample of blood is taken. Then the person drinks a liquid that has glucose (sugar) in it. Two hours later, another sample of blood is taken to see how the body processes the glucose in the blood.

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Pancreas
An organ behind the lower part of the stomach that is about the size of a hand. It makes insulin so the body can use glucose (sugar) for energy.
Peripheral arterial disease (PAD)
A cardiovascular condition in which the blood vessels in the legs become narrow or blocked. This increases the risk of heart attack, stroke, and serious infection of the legs and feet, which could lead to amputation.
Peripheral neuropathy
A type of nerve damage most commonly affecting the feet and legs. The arms, abdomen, and back may rarely be affected.
Peripheral vascular disease (PVD)
Any abnormal condition that affects the blood vessels outside the heart and lymphatic vessels. Often occurs as decreased blood flow to the hands and feet. People who have had diabetes for a long time may develop PVD.
Podiatrist
A health professional who diagnoses and treats foot problems.
Polydipsia
Excessive thirst that lasts for long periods of time; may be a sign of diabetes.
Polyphagia
Excessive hunger and eating; may be a sign of diabetes. People with polyphagia often lose weight even though they are eating more than normal.
Polyuria
Increased need to urinate often; a common sign of diabetes.
Prediabetes
A condition defined by a person having blood glucose levels that are higher than normal, but not high enough to be considered diabetes.
Protein
One of three main classes of food. Proteins are made of amino acids, which are called the "building blocks of the cells." The cells need proteins to grow and to mend themselves. Protein is found in many foods such as meat, fish, poultry, eggs, legumes and dairy products.
Random plasma glucose test
A blood test sometimes used to diagnose diabetes during a regular health checkup. It doesn’t require fasting beforehand. If the RPG measures 200 mg/dL or above, and the individual also shows symptoms of diabetes, such as excessive thirst, excessive urination, or excessive hunger, then a provider may diagnose diabetes.
Rebound effect
See: Somogyi effect
Regular insulin
A type of insulin that is short-acting.
Renal
Relating to the kidneys.
Renal threshold
The point at which the blood is holding so much of a substance, such as glucose, that the kidneys allow the excess to "spill" into the urine. This is also called "kidney threshold," "kidney spilling point" or "leak point."
Retina
The part of the back lining of the eye that senses light. It has many small blood vessels that are sometimes harmed when a person has had diabetes for a long time.
Retinopathy
A disease of the small blood vessels in the retina of the eye.
Risk factor
Anything that increases the chance of a person developing a disease or condition.
Rubella
A contagious disease caused by a virus that is usually accompanied with mild illness such as a low-grade fever, sore throat, or a rash.
Self blood glucose monitoring
See: Home blood glucose monitoring
Shared decision making
A process in which providers and patients work together to make decisions about selecting tests, treatments, and care plans. The goal is to balance risks and expected outcomes with the patient’s preferences and values.
Sucrose
Table sugar; a form of sugar that the body must break down into a more simple form before the blood can absorb it and take it to the cells.
Sugar
A class of carbohydrates that taste sweet. Sugar is a quick and easy fuel for the body to use. Some types of sugar are lactose, glucose, fructose, and sucrose.
Sulfonylureas
Pills or capsules that people take to lower the level of glucose in the blood. This medication stimulates the pancreas to make insulin.
Transient ischemic attack (TIA)
A health event that is caused by a temporary blockage in a blood vessel that leads to the brain.
Triglyceride
Fats carried in the blood from the food we eat. Most of the fats we eat, including butter, margarines, and oils, are in triglyceride form. Excess calories, alcohol, or sugar in the body are converted into triglycerides and stored in fat cells throughout the body. The body needs insulin to remove this type of fat from the blood.
Type 1 diabetes
An autoimmune disease in which the insulin-producing cells (called beta cells) of the pancreas are damaged. People with type 1 diabetes produce little or no insulin, so glucose cannot get into the body’s cells for use as energy. This causes blood glucose to rise. People with type 1 diabetes must use insulin injections to control their blood glucose.
Type 2 diabetes
A type of diabetes in which the insulin produced is either not enough or doesn’t work properly in the body. When there is not enough insulin or the insulin is not used as it should be, glucose cannot get into the body’s cells for use as energy. This causes blood glucose to rise.
U-100
See: Unit of insulin
Ulcer
A break in the skin; a deep sore. People with diabetes may develop ulcers from minor scrapes on the feet or legs, from cuts that heal slowly, or from the rubbing of shoes that don’t fit well. Ulcers can become infected and should be treated promptly.
Ultralente insulin
A type of insulin that is very long acting.
Unit of insulin
The basic measure of insulin. U-100 is the most common concentration of insulin. U-100 means that there are 100 units of insulin per milliliter (ml) of liquid.
Unstable diabetes
See: Brittle diabetes
Urine ketone testing
Checking urine to see if it contains ketones. The presence of ketones could be a sign of serious illness.
Urologist
A doctor who specializes in treatment of the urinary tract for men and women, and treatment of the genital organs for males.
Vascular
Relating to the body’s blood vessels (arteries, veins and capillaries).
Vein
A blood vessel that carries blood to the heart.
Vitrectomy
A procedure in which the gel from the center of the eyeball is removed because it has blood and scar tissue in it that blocks vision. An eye surgeon replaces the clouded gel with a clear fluid.