Medical Tests


IDDM (Insulin-Dependent Diabetes Mellitus): Former term for type 1 diabetes.

Idiopathic Diabetes: A subtype of type 1 diabetes, treated the same as type 1 with insulin. Idiopathic means “of unknown origin.”

Immune System: The body’s system for protecting itself from viruses and bacteria or any “foreign” substances.

Immunosuppressant: A drug that suppresses the natural immune responses. Immunosuppressants are given to transplant patients to prevent organ rejection or to patients with autoimmune diseases.

Impaired Fasting Glucose (IFG): A condition in which a blood glucose test, taken after an 8- to 12-hour fast, shows a level of glucose higher than normal but not high enough for a diagnosis of diabetes. IFG, also called pre-diabetes, is a level of 100 mg/dL to 125 mg/dL. Most people with pre-diabetes are at increased risk for developing type 2 diabetes.

Impaired Glucose Tolerance (IGT): A condition in which blood glucose levels are higher than normal but are not high enough for a diagnosis of diabetes. IGT, also called pre-diabetes. is a level of 140 mg/dL to 199 mg/dL 2 hours after the start of an oral glucose tolerance test. Most people with pre-diabetes are at increased risk for developing type 2 diabetes. Other names for IGT that are no longer used are “borderline,” “subclinical,” “chemical,” or “latent” diabetes.

Implantable Insulin Pump: A small pump placed inside the body to deliver insulin in response to remote-control commands from the user.

Impotence: The inability to get or maintain an erection for sexual activity. Also called erectile dysfunction.

Incidence: The number of new cases of a disease among a particular group of people over a certain period of time (how often a disease occurs).

Incontinence: Loss of bladder or bowel control; the accidental loss of urine or feces.
Inhaled Insulin: A treatment for taking insulin using a portable device that allows a person to breathe in insulin. In 2008, inhaled insulin was discontinued in the United States because of its unpopularity and inconsistencies in dosing.

Injection: Inserting liquid medication or nutrients into the body with a syringe. A person with diabetes may use short needles or pinch the skin and inject at an angle to avoid an intramuscular injection of insulin.

Injection Site Rotation: Changing the places on the body where insulin is injected. Rotation prevents the formation of lipodystrophies (scarring of tissue).

Injection Sites: Places on the body where insulin is usually injected.

Insertion Site: Where a cannula is placed on the body when using an insulin pump.
Insulin: A hormone that helps the body use glucose for energy. The beta cells of the pancreas make insulin. When the body cannot make enough insulin, insulin is taken by injection or through use of an insulin pump.

Insulin Adjustment: A change in the amount of insulin a person with diabetes takes based on factors such as meal planning, activity, and blood glucose levels.

Insulin-Dependent Diabetes Mellitus (IDDM): Former term for type 1 diabetes.

Insulinoma: A tumor of the beta cells in the pancreas. An insulinoma may cause the body to make extra insulin, leading to hypoglycemia.

Insulin Allergy: A rare allergy to insulin, or an additive in the insulin. A person with allergic reaction to insulin may experience hives, asthmatic reactions, swelling, and changes in heart rate after injections of insulin. It is treated by desensitization (which usually requires hospitalization) or by using a purified insulin.

Insulin Analog: A man-made (synthetic) form of insulin. In analog insulin certain amino acids substitute for the ones found naturally on an insulin molecule. Currently, three types of analog insulin are commercially available (see IOH Drug News for more information) on insulin lispro (Humalog), insulin aspart (Novalog/NovaRapid), and insulin glargine (Lantus).

Insulin Antagonist: Anything that opposes the action of insulin (opposite of, or fights the action of insulin). Since insulin lowers blood glucose, the opposite (or agonist) to insulin would be glucagon, a hormone that acts to raise blood sugar.

Insulin Binding: Insulin binds (or attaches) to other cells in the body. When insulin binds to a cell that needs energy it acts as a key opening the cell so that it can take in sugars from the blood stream. Sometimes insulin will bind to proteins designed to protect the body from antibodies (outside, or foreign substances).

Sometimes, injected insulin is seen as an antibody to the body and it binds with protein. In this case, insulin does not work as well as when it binds directly to body cells.

An insulin pen can be used to inject insulin to treat diabetes.
An insulin pen can be used to inject insulin to treat diabetes.
An insulin pump is a deviced used to administer insulin without the need for shots.
An insulin pump is a deviced used to administer insulin without the need for shots.

Insulin Pen: A device for injecting insulin that looks like a fountain pen and holds replaceable cartridges of insulin. Also available in disposable form.

Insulin Pump: An insulin-delivering device about the size of a deck of cards that can be worn on a belt or kept in a pocket. An insulin pump connects to narrow, flexible plastic tubing that ends with a needle inserted just under the skin. Users set the pump to give a steady trickle or basal amount of insulin continuously throughout the day. Pumps release bolus doses of insulin (several units at a time) at meals and at times when blood glucose is too high, based on programming done by the user.

Insulin Reaction: When the level of glucose (sugar) in the blood is too low (at or below 70 mg/dL) the body reacts. Also known as insulin shock or hypoglycemia.

Insulin Receptors: Areas on the outer part of a cell that allow the cell to bind with insulin in the blood. When the cell and insulin bind, the cell can take glucose from the blood and use it for energy.

Insulin Resistance: The body’s inability to respond to and use the insulin it produces. Insulin resistance may be linked to obesity, hypertension, and high levels of fat in the blood.

Insulin Sensitizer: When a person is insulin resistant medications may help increase sensitivity to insulin. Most commonly prescribed (usually for type 2 or pre-diabetes) are: Glucophage (metformin), Avandia and Actos (both from the “glitazone classification of drugs). Reducing caffeine intake may also help increase insulin sensitivity, as does minimizing processed carbohydrates in the diet, losing weight, and regular exercise. Some studies indicate the supplement chromium may help increase insulin sensitivity but should only be taken under the advice of a physician.

Insulin Shock: See hypoglycemia. Or read our main sections on Insulin Shock and Hypoglycemia.

Intensive Therapy: A treatment for diabetes in which blood glucose is kept as close to normal as possible through frequent injections or use of an insulin pump; meal planning; adjustment of medicines; and exercise based on blood glucose test results and frequent contact with a person’s health care team.

Intermediate-Acting Insulin: A type of insulin that starts to lower blood glucose within 1 to 2 hours after injection and has its strongest effect 6 to 12 hours after injection, depending on the type used. See lente insulin and NPH insulin.

Intramuscular Injection: Inserting liquid medication into a muscle with a syringe. Glucagon may be given by subcutaneous or intramuscular injection for hypoglycemia.

Intravenous (IV): Injecting liquid medication or nourishment into the body by needle or catheter directly into a vein.

Islet Cell Antibodies (ICA): Proteins found in the blood of people newly diagnosed with type 1 diabetes. They are also found in people who may be developing type 1 diabetes. The presence of ICA indicates that the body’s immune system has been damaging beta cells in the pancreas.

Presence of antibodies for any disease (including Hashimoto’s, hemochromatosis, etc.) indicates that the body has begun an autoimmune response and is attacking healthy cells in the body.

Islet Cell Transplantation: Moving the islets from a donor pancreas into a person whose pancreas has stopped producing insulin. Beta cells in the islets make the insulin that the body needs for using blood glucose.

Islet Cells: Groups of cells located in the pancreas that make hormones to help the body break down and use food. There are five types of cells in an islet:

  • Alpha cells that make glucagon, which raises the level of glucose (sugar) in the blood; Beta cells that make insulin;
  • Delta cells that make somatostatin a hormone that inhibits the release of numerous other hormones in the body; and
  • PP cells and D1 cells, about which little is known.

Islets of Langerhans: The insulin-producing tissue in the pancreas consisting of specialized cells that make and secrete hormones.