Name: Diabetes glossary
Published: 2026-09-02T00:00:00Z

The disease and its forms

diabetes mellitus: Chronic disease in which blood glucose rises above normal, either because insulin is missing or because it does not act well enough.
type 1 diabetes: Form of diabetes in which the immune system destroys the beta cells of the pancreas, so the body's own insulin production almost disappears. Insulin treatment is needed from diagnosis.
type 2 diabetes: Form of diabetes in which the body produces insulin but does not use it efficiently, and production gradually declines over time. It is the most common form of diabetes.
gestational diabetes: Diabetes discovered for the first time during pregnancy, which usually goes away after birth.
secondary diabetes: Diabetes caused by another disease or by a treatment, for example by diseases of the pancreas or by corticosteroids.
pancreatic (pancreatogenic) diabetes: Secondary diabetes that appears after damage to the pancreas from pancreatitis, pancreatic surgery or other pancreatic diseases.
LADA: Autoimmune diabetes that starts in adulthood, progresses more slowly than classic type 1 diabetes and can be mistaken at first for type 2.
MODY: Group of rare forms of diabetes caused by a change in a single gene, usually passed down in families from one generation to the next.
prediabetes: Stage in which blood glucose is above normal but does not yet reach the threshold for diabetes. The risk of progressing to diabetes is increased.
onset: The moment when the disease becomes apparent and the diagnosis is made.
remission ("honeymoon"): Period at the start of type 1 diabetes treatment in which the remaining beta cells still produce insulin, so the need for injected insulin drops a lot.
relapse after remission: The end of the remission period, when the body's own insulin production falls again and insulin doses have to be increased.
stages of type 1 diabetes: The three stages of the disease. Stage 1 has autoantibodies with normal glucose, stage 2 adds mildly abnormal glucose, and stage 3 is the clinically manifest disease.
long-term course: The way the disease and the risk of complications change over the years under treatment.

Physiology and immunology

pancreas: Organ located behind the stomach that produces digestive enzymes and hormones, among them insulin and glucagon.
beta cells: The cells in the islets of Langerhans that produce insulin. In type 1 diabetes they are destroyed by the immune system.
islets of Langerhans: Small clusters of hormone-producing cells scattered through the pancreas, which contain the insulin-producing beta cells.
insulin (the hormone): Hormone produced by the beta cells that lets glucose enter the cells and thereby lowers blood glucose.
glucagon: Hormone produced by the pancreas with the opposite effect to insulin. It raises blood glucose by releasing glucose from the liver.
C-peptide: Fragment released into the blood together with the body's own insulin, used as a measure of the remaining insulin production.
glucose: Simple sugar that circulates in the blood and is the main energy source of the cells.
blood glucose: The concentration of glucose in the blood, expressed in mg/dL or in mmol/L.
autoimmunity: Faulty reaction of the immune system, which attacks the body's own structures.
autoimmune process: The set of immune reactions directed against the beta cells, which gradually leads to their destruction.
autoantibodies: Antibodies directed against the body's own structures. In type 1 diabetes they appear months or years before symptoms and help with diagnosis.
anti-GAD antibodies (GADA): Autoantibodies against the GAD enzyme of the beta cells, the most frequent ones at the onset of autoimmune diabetes in adults.
anti-IA-2 antibodies (IA-2A): Autoantibodies against the IA-2 protein of the beta cells, used in the diagnosis of autoimmune diabetes.
anti-ZnT8 antibodies (ZnT8A): Autoantibodies against the zinc transporter 8 of the beta cells.
insulin autoantibodies (IAA): Autoantibodies against the body's own insulin, frequent especially in young children with type 1 diabetes.
insulitis: Inflammation of the islets of Langerhans produced by the autoimmune attack on the beta cells.
immune system: The set of cells and molecules that defend the body against infections. In autoimmune diseases it also attacks the body's own structures.
T lymphocytes: Immune cells with a central role in the destruction of beta cells in type 1 diabetes.
cellular immunity: The part of immunity carried out directly by cells, especially T lymphocytes, rather than by antibodies.
genetic predisposition: Inheriting gene variants that increase the risk of disease without making it inevitable.
HLA: The main system of immunity genes, called the human leukocyte antigen. Certain HLA variants significantly increase the risk of type 1 diabetes.
molecular mimicry: Resemblance between a microbial structure and one of the body's own, which can trick the immune system into attacking the body's own cells too.
gut microbiome: All the microorganisms living in the gut. It influences how immunity develops and is studied as a factor in type 1 diabetes.
environmental factors: Elements outside the genes, such as infections or diet, that can contribute to triggering the disease.
viral and bacterial infections: Infections studied as possible triggers or accelerators of the autoimmunity of type 1 diabetes.
enteroviruses: Family of viruses common in children, studied as a possible trigger of the autoimmunity of type 1 diabetes.
vitamin D: Vitamin with a role in immunity and in bone health. Low levels have been associated with a higher risk of type 1 diabetes.
nutritional factors: Elements of early-life nutrition studied in relation to the risk of type 1 diabetes, for example the duration of breastfeeding or the age at which gluten is introduced.
perinatal factors: Circumstances around birth, such as birth weight or cesarean delivery, associated with small variations in the risk of type 1 diabetes.
beta-cell preservation: The strategies that try to keep the remaining beta cells alive, from early diagnosis to immune therapies.
cortisol: Hormone produced by the adrenal glands that raises blood glucose. More of it is released in stress and in illness, and corticosteroid treatment has the same effect.
glycogen: The form in which the body stores glucose, mainly in the liver and in muscle. The liver turns it back into glucose when blood glucose falls.
adrenaline: Hormone released quickly in stress and in hypoglycemia. It raises blood glucose and produces the warning symptoms of hypoglycemia: shaking, palpitations, sweating.
gluten: Protein found in wheat, barley and rye. It matters in type 1 diabetes because celiac disease, in which gluten damages the small intestine, is more common in these patients than in the general population.

Symptoms and onset

polyuria: Frequent and abundant urination, one of the classic signs of high blood glucose.
polydipsia: Intense and persistent thirst, which usually accompanies polyuria at the onset of diabetes.
dehydration: Excessive loss of water from the body, common at the onset of diabetes because of abundant urination.
classic onset: The disease setting in with the typical signs, that is intense thirst, frequent urination, weight loss and tiredness.
silent (slow) onset: The disease setting in without obvious symptoms, sometimes discovered only through tests or screening.
onset with ketoacidosis: Severe form of onset in which the diagnosis is made only once diabetic ketoacidosis has developed.

Laboratory and diagnosis

fasting glucose: Blood glucose measured in the morning after at least 8 hours without food. Values of 126 mg/dL (7.0 mmol/L) or higher, confirmed on a second test, establish the diagnosis of diabetes.
random glucose: Blood glucose measured at any time of day, regardless of meals. A value of 200 mg/dL (11.1 mmol/L) or higher, together with typical symptoms, establishes the diagnosis of diabetes.
glycated hemoglobin (HbA1c): The percentage of hemoglobin that glucose has attached to. It reflects the average blood glucose of the last 2–3 months.
estimated average glucose (eAG): The average blood glucose calculated from HbA1c, expressed in the same units as everyday glucose readings.
OGTT: The oral glucose tolerance test. It measures blood glucose before and 2 hours after a standard drink containing 75 g of glucose.
diagnostic criteria: The internationally agreed thresholds of blood glucose and HbA1c from which diabetes is diagnosed.
screening: Testing people without symptoms in order to discover the disease or its risk as early as possible.
ketone bodies: Substances produced by the liver when cells cannot use glucose and burn too much fat. Without insulin they build up dangerously.
ketonemia: The presence of ketone bodies in the blood, measurable with rapid tests.
ketonuria: The presence of ketone bodies in the urine, detectable with test strips.
glycosuria: The presence of glucose in the urine. It appears when blood glucose exceeds the renal threshold of about 180 mg/dL (10.0 mmol/L).
serum creatinine: Blood test that reflects kidney function and enters the eGFR calculation.
AST (transaminase): Liver enzyme measured in the blood, used among other things in the FIB-4 score for liver fibrosis.
ALT (transaminase): Liver enzyme measured in the blood together with AST, used in the same FIB-4 score for liver fibrosis.
HDL cholesterol: The cholesterol fraction that carries cholesterol from the vessel walls back to the liver. Higher values are usually desirable, which is why it is called "good cholesterol".
LDL cholesterol: The cholesterol fraction that builds up in the artery wall. Higher values raise the risk of heart attack and stroke, which is why it is called "bad cholesterol".
platelets: The blood cells involved in clotting. Their count enters the calculation of the FIB-4 score.
eGFR: The estimated glomerular filtration rate, that is the standard measure of kidney function, calculated from creatinine, age and sex.
kidney function: The kidneys' ability to filter the blood, monitored regularly in people with diabetes.
liver fibrosis: Gradual scarring of the liver. Its risk can be estimated noninvasively with the FIB-4 score.

Acute complications

hypoglycemia: A drop in blood glucose below 70 mg/dL (3.9 mmol/L). It causes shakiness, sweating, hunger and the need to eat fast-acting carbohydrates right away.
severe hypoglycemia: Hypoglycemia in which the person needs someone else's help to recover.
hyperglycemia: A rise in blood glucose above the target values.
diabetic ketoacidosis: Serious acute complication caused by lack of insulin, with a buildup of ketone bodies and acidification of the blood. It is a medical emergency.
hypoglycemic coma: Loss of consciousness caused by severe hypoglycemia.
treatment of hypoglycemia: Rapid correction of blood glucose with about 15 g of fast-acting carbohydrates, repeated if needed after 15 minutes.
emergency glucagon: Medicine that raises blood glucose quickly, used in severe hypoglycemia when the person cannot swallow.

Insulin therapy

insulin therapy: Treatment with insulin given from outside the body, indispensable in type 1 diabetes.
basal insulin: The long-acting insulin that covers the body's needs between meals and overnight.
prandial insulin (bolus): The insulin given at meals to cover the carbohydrates eaten.
rapid-acting insulin: Insulin analog for meals that starts working in 10–20 minutes and lasts 3–5 hours.
ultra-rapid insulin: Mealtime analog with an even faster start, suited to injection right before the meal.
long-acting insulin: Basal insulin with a profile as flat as possible, covering about 24 hours or more. The slow analogs used today are glargine and degludec.
intermediate-acting insulin (NPH): Human basal insulin lasting about 12–16 hours, used less often today than the slow analogs.
human insulin: Insulin identical to the one produced by humans, obtained through biotechnology. Its forms are regular insulin for meals and NPH as basal.
insulin analogs: Insulins slightly modified from human insulin to give a more convenient action profile, either faster or slower and more stable.
basal-bolus regimen: The treatment regimen that combines a basal insulin with meal and correction boluses, the closest to natural secretion.
multiple daily injections: Delivering the basal-bolus regimen through several injections a day with an insulin pen.
insulin dose: The amount of insulin given at one time, expressed in international units.
insulin pen: Pen-shaped injection device with an insulin cartridge and a dose selector.
pen needle: Short single-use needle attached to the pen for each injection.
injection technique: The correct way of giving insulin under the skin, which directly influences how it is absorbed.
injection site rotation: Systematically changing the injection site in order to prevent lipohypertrophy.
lipohypertrophy: Thickening of the fatty tissue at repeatedly injected sites, which makes insulin absorption unpredictable.
insulin-to-carbohydrate ratio (ICR): The number of grams of carbohydrate covered by one unit of insulin, used to calculate the meal bolus.
correction factor (ISF): The number of mg/dL by which one unit of insulin lowers blood glucose, used to calculate the correction dose.
correction dose: Extra insulin given to bring a high blood glucose back to target.
active insulin: The insulin still left in the body from an earlier bolus, which keeps lowering blood glucose and is checked before every correction dose. It is also called insulin on board (IOB).
insulin degludec: Basal insulin with a very long action that covers more than 24 hours and is given once a day.
insulin glargine: Long-acting basal insulin, usually given once a day. It exists in two concentrations, which are not interchangeable without the doctor's instruction.
teplizumab: Monoclonal antibody that delays the move from stage 2 to stage 3 of type 1 diabetes, in people with autoantibodies and already altered blood glucose.

Glucose sensors

glucose sensor: Device worn on the body that measures glucose every few minutes, without repeated finger pricks.
continuous glucose monitoring (CGM): Automatic measurement of glucose day and night with a sensor, showing the values and the trend.
real-time sensor: Sensor that automatically sends every value to the phone or receiver and can raise alarms on its own.
intermittently scanned sensor: Sensor that shows the value when the phone or the sensor reader is brought close to it.
transcutaneous sensor: Sensor with a thin filament inserted through the skin, usually worn for 7–15 days.
implantable sensor: Sensor placed completely under the skin through a minor procedure, with a working life of several months.
interstitial fluid: The fluid between the cells, where sensors actually measure glucose.
sensor-to-blood lag: The delay of a few minutes between the interstitial fluid value and blood glucose, visible mainly during rapid changes.
calibration: Adjusting the sensor against a finger-prick glucose reading. Modern sensors come factory-calibrated.
warm-up period: The interval after insertion during which the sensor does not yet show values.
accuracy: How close the sensor values are to the real blood glucose.
adjunctive use: Using the sensor only as additional information, with treatment decisions confirmed by a glucose meter.
non-adjunctive use: Using the sensor directly for dosing decisions, without confirmation by a glucose meter.
integrated sensor (iCGM): Sensor certified to communicate safely with other devices, for example with automated pumps.
interoperability: The ability of sensors, pumps and algorithms from different manufacturers to work together.
transmitter: The part of the sensor that sends the values wirelessly to the phone or receiver.
receiver: Dedicated device that displays the sensor values, used instead of a phone.
applicator: The device with which the sensor is placed on the skin with a simple press.
alarms: The sensor's sound or vibration warnings at low, high or rapidly changing glucose.
trend arrows: The arrows on the display that show the direction and speed of change of glucose.
glucose meter: The classic device that measures blood glucose from a drop of blood from the finger.
finger prick: Collecting the drop of blood for the glucose meter with a lancing device.
professional sensor: Sensor placed in the clinic and worn for a short period, with the data analyzed by the doctor at the end.
wear time: The number of days a sensor keeps measuring after insertion, set by the manufacturer.
data transmission and storage: The path of the values from the sensor to apps and platforms, where the care team or family can also see them.

Insulin pumps

insulin pump: Device worn on the body that delivers rapid-acting insulin continuously under the skin and replaces multiple injections.
tubed pump: Pump carried in a pocket or on a belt, connected to the body by a thin tube and an infusion set.
tubeless (patch) pump: Small pump stuck directly on the skin and controlled remotely, with no external tube.
basal insulin patch: Patch-type device that delivers only basal insulin, at a constant rate.
bolus patch: Patch-type device that delivers only mealtime boluses, by pressing.
implantable pump: Pump placed surgically in the abdomen, which releases insulin inside the body. It is used rarely, in special situations.
basal rate: The small amount of insulin the pump delivers every hour, which replaces injected basal insulin.
bolus: The insulin dose delivered at one time, at a meal or for correction.
infusion set: The tubing and cannula assembly that carries insulin from the pump under the skin. It is changed every 2–3 days.
cannula: The very thin plastic or steel tube inserted under the skin, through which insulin enters.
catheter: The generic name for the tubing through which the pump delivers insulin.
reservoir: The container inside the pump that is filled with rapid-acting insulin.
occlusion: Blockage of the insulin flow in the tube or cannula, signaled by the pump alarm. Left untreated, it quickly leads to hyperglycemia and ketosis.
continuous subcutaneous infusion: The medical term for the uninterrupted delivery of insulin under the skin, carried out by the pump.
hybrid closed loop: System in which the algorithm automatically adjusts basal insulin according to the sensor values, while meal boluses remain up to the user.
automated insulin delivery system: The combination of pump, sensor and algorithm that adjusts insulin delivery on its own.
mimicking natural secretion: The goal of modern treatment, namely reproducing as faithfully as possible the way a healthy pancreas releases insulin.

Nutrition and lifestyle

carbohydrates: The nutrients in food that raise blood glucose directly, from simple sugars to starch.
carbohydrate counting: Estimating the grams of carbohydrate in each meal, the basis for calculating the bolus in type 1 diabetes.
glycemic index: A measure of how fast a food raises blood glucose, compared with pure glucose.
portion: The amount of food actually eaten, expressed in grams or in household measures.
physical activity: Any movement that uses energy. It usually lowers blood glucose and calls for adjusting doses or adding snacks.
overweight: Weight above the normal range, defined in adults by a BMI of 25 kg/m² or more.

Scores and calculators

body mass index (BMI): The ratio of weight to the square of height, used to classify weight in adults.
eGFR CKD-EPI 2021: The current standard formula for estimating kidney function in adults, from creatinine, age and sex.
Schwartz formula: The formula for estimating eGFR in children, which uses height and creatinine.
FIB-4: Score calculated from age, transaminases and platelets, which estimates the risk of liver fibrosis.
FINDRISC: Validated questionnaire that estimates the risk of developing type 2 diabetes within the next 10 years.
PREVENT: A set of American Heart Association equations that estimates cardiovascular risk over 10 and over 30 years, using kidney function as well.
PHQ-9: A nine-question questionnaire about the last two weeks, used for orientation in depression. It does not make the diagnosis on its own.
GAD-7: A seven-question questionnaire about the last two weeks, used for orientation in anxiety. It does not make the diagnosis on its own.
unit converter: Tool that converts lab values between units, for example blood glucose between mg/dL and mmol/L.
percentile: The position of a value against a reference group of the same age and sex. The 50th percentile is the middle value of the group.

Epidemiology and psychology

incidence: The number of new cases appearing in a population over a period of time, usually one year.
prevalence: The total number of people living with the disease at a given moment in a population.
mortality: The frequency of deaths associated with the disease in a population, tracked to measure progress in care.
life expectancy: The average number of years left to live, estimated statistically. It is an indicator followed constantly in diabetes studies.
stress: The body's reaction to demands. Stress hormones raise blood glucose, and psychological stress interferes with daily self-care.
psychological impact: The emotional burden of a chronic disease, from exhaustion to anxiety, which deserves to be discussed openly with the care team.
psychological support: Specialized or community help for the emotional burden of diabetes.
associated autoimmune diseases: Other autoimmune diseases that are more frequent in people with type 1 diabetes, first of all autoimmune thyroiditis and celiac disease.
autoimmune thyroiditis: Autoimmune inflammation of the thyroid gland, the most frequent disease associated with type 1 diabetes.
celiac disease: Autoimmune intolerance to gluten, looked for periodically through blood tests in people with type 1 diabetes.

Chronic complications

diabetic retinopathy: Damage to the small vessels of the retina, caused by high blood glucose maintained over years. It is found by examining the back of the eye before it causes symptoms.
diabetic neuropathy: Damage to the nerves, most often in the feet, with numbness, tingling or pain. It can reduce sensation, so wounds go unnoticed.
diabetic nephropathy: Damage to the kidneys, followed through albumin in the urine and through the estimated glomerular filtration rate.

Oral medicines

metformin: Oral medicine used as the first choice in type 2 diabetes. It lowers the glucose the liver produces and does not by itself cause hypoglycemia.
sulfonylureas: Class of oral medicines used in type 2 diabetes that make the beta cells release insulin. They can cause hypoglycemia, unlike metformin.

Abbreviations

ADA: American Diabetes Association, the author of the annual standards of care.
AST: aspartate aminotransferase, a transaminase used in the FIB-4 score.
CGM: continuous glucose monitoring.
CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration, the standard formula for calculating eGFR.
DM: diabetes mellitus.
eAG: estimated average glucose, calculated from HbA1c.
EASD: European Association for the Study of Diabetes.
eGFR: estimated glomerular filtration rate.
FIB-4: Fibrosis-4, the score that estimates the risk of liver fibrosis.
FINDRISC: Finnish Diabetes Risk Score, the type 2 diabetes risk questionnaire.
GADA: autoantibodies against glutamic acid decarboxylase (GAD).
HbA1c: glycated hemoglobin.
carbs: carbohydrates.
HLA: human leukocyte antigen.
IA-2A: autoantibodies against the IA-2 protein of the beta cells.
IAA: insulin autoantibodies.
ICD-10: International Classification of Diseases, 10th revision.
iCGM: integrated CGM, the integrated sensor certified for interoperability.
ICR: insulin-to-carbohydrate ratio.
BMI: body mass index.
ISF: insulin sensitivity factor, also called the correction factor.
ISPAD: International Society for Pediatric and Adolescent Diabetes.
LADA: latent autoimmune diabetes in adults.
MODY: maturity-onset diabetes of the young, monogenic diabetes with onset at a young age.
NPH: neutral protamine Hagedorn, the intermediate-acting human insulin.
WHO: World Health Organization.
OGTT: oral glucose tolerance test.
IU: international unit, the unit of measurement for insulin doses.
ZnT8A: autoantibodies against the zinc transporter 8.