Diabetes: Glossary, symptoms & diagnosis health library

Diabetes is a chronic disease of inadequate control of blood glucose levels. The body is not able to take up glucose into the cells and use if for energy, causing buildup of extra glucose in the bloodstream. Insulin is a hormone made by the pancreas, which helps the glucose from the food you eat to get into the cells to be used for energy. When there is not insulin or not enough insulin, the glucose stays in the blood and doesn’t go into the cells for energy. 5

Diabetes can be classified into type 1, type 2, gestational diabetes, neonatal diabetes, steroid induced diabetes, and maturity onset diabetes of the young. Type 1 diabetes is the result of defective insulin secretion and type 2 is the result of defective insulin action. In the United States (U.S.), it is the seventh leading cause of death.1 It is estimated that, in the U.S., 34.2 million people have diabetes, or one in 10 people. 2

The cause of type 1 and type 2 diabetes differs and so differs the presentation and treatment of each. Uncontrolled diabetes can lead to damage of body tissues and organs such as the heart, kidney, eyes, and nerves.


Type 1 – This is an autoimmune disease. The cells that produce insulin in the pancreas are destroyed. The onset is usually in children and young adults. Due to the pancreas not producing any insulin or very little insulin, people with type 1 diabetes must inject insulin every day.

Type 2 – This is the most common cause of diabetes. The body is not producing enough insulin or the body’s cells are not responding to the insulin. The onset of type 2 is middle age and older, and it’s usually due to obesity.

Gestational diabetes – This type occurs during pregnancy, and it usually goes away once the pregnancy is over. People with gestational diabetes have higher risk of developing type 2 diabetes later in life.

Steroid induced diabetes – This is an abnormal increase in blood glucose due to use of glucocorticoids in a patient with or without a prior history of diabetes mellitus. 7

Neonatal diabetes - is highly likely to be due to an underlying monogenic defect when it occurs under 6 months of age. 6

Maturity onset diabetes in the young- This is a monogenic diabetes first described as a mild and asymptomatic form of diabetes that was observed in non-obese children, adolescents, and young adults. 8

Prediabetes – This is when the body’s glucose levels are higher than normal, but the body is still producing insulin.


The most common symptoms for type 1 diabetes are urinating often, feeling very thirsty, feeling very hungry (even though you are eating), extreme fatigue, blurry vision, cuts/bruises that are slow to heal, and weight loss—even though you are eating more. 9

The most common symptoms for type 2 diabetes are increased urination, increased thirst, and blurred vision. Your doctor will order blood test, including a random blood glucose test, a fasting blood glucose test, and a hemoglobin A1C. A fasting glucose should be less than 100 mg/dL. A fasting glucose level of 126 mg/dL or higher can be diagnosed as diabetes. Another indicator is a random blood glucose of 200 mg/dL or higher or an A1C of 6.5 % or higher.

If the results are below those ranges but close to them, you may have “prediabetes”, meaning you have an increased risk to develop diabetes. You may have positive changes if you improve your diet and increase exercise and stop smoking.

Understanding A1C

This test measures the glycated hemoglobin (A1C). It measures your average blood glucose over the last two to three months.

  • Below 5.7% is normal.
  • 5.7% to 6.4% is “prediabetes”.
  • 6.5% or higher on two separate tests indicates diabetes.

Your doctor will also need to determine if you have type 1 or type 2 diabetes. Sometimes it’s easy to determine but other times it will depend on your family history of autoimmune diseases such as hypothyroidism, hyperthyroidism, or celiac disease. Symptoms of frequent urination and weight loss is suspected to be type 1. Another indicator of type one is having high blood glucose levels even after starting type 2 diabetes treatments, such as oral anti-diabetic medication. 3

For gestational diabetes an oral glucose tolerance test is used. You will need to fast overnight and then drink a sugary drink provided at the doctor’s office. Then your glucose levels will be tested periodically for the next two hours. A reading less than 140 mg/dL is normal, 140-100 mg/dL is prediabetes, and over 200 mg/dL after two hours suggest diabetes.

Managing diabetes will require healthy eating, regular exercise, weight loss, oral medication, or insulin therapy, and monitoring of blood glucose. 4


Depending on your glucose levels and blood work, your doctor may prescribe oral medications or a combination of medications, including insulin. There are different types of oral medications that help your body regulate blood glucose. For people with type 1 diabetes, insulin injections are the only treatment. For type 2 diabetes, treatments can vary. This will depend on how you are eating and how much exercise you do, and over time the treatment may change depending on how you respond to the medications. It’s important to see your doctor regularly to keep up with your treatment.

  1. Sapra A, Bhandari P. Diabetes Mellitus. [Updated 2021 Sep 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan- Available from: https://www.ncbi.nlm.nih.gov/books/NBK551501/
  2. Cleveland Clinic. Diabetes: An Overview. https://my.clevelandclinic.org/health/diseases/7104-diabetes
  3. Wexler, D., Nathan, D., and Mulder, J. Patient education: Type 2 diabetes: Overview (Beyond the Basics). July 20, 2020 https://www.uptodate.com/contents/type-2-diabetes-overview-beyond-the-basics
  4. The Mayo Clinic. Type 2 Diabetes. January 20, 2021. https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/diagnosis-treatment/drc-20351199
  5. Centers for Disease Control and Prevention. (2022, July 7). What is diabetes? Centers for Disease Control and Prevention. Retrieved August 10, 2022, fromhttps://www.cdc.gov/diabetes/about/
  6. Dahl, A., & Kumar, S. (2020, February 12). Recent advances in neonatal diabetes: DMSO. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. Retrieved August 10, 2022, from https://www.dovepress.com/recent-advances-in-neonatal-diabetes-peer-reviewed-fulltext-article-DMSO
  7. Hwang JL, Weiss RE. Steroid-induced diabetes: a clinical and molecular approach to understanding and treatment. Diabetes Metab Res Rev. 2014;30(2):96-102. doi:10.1002/dmrr.2486
  8. Hoffman LS, Fox TJ, Anastasopoulou C, et al. Maturity Onset Diabetes in the Young. [Updated 2021 Sep 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532900/
  9. Diabetes Symptoms. 2021. American Diabetes Association. https://diabetes.org/diabetes/type-1/symptoms

provided below:

What is diabetes?

  • Introduction to diabetes: Look through a collection of resources on topics ranging from prediabetes to the main types of diabetes, what to do when diagnosed, and how to manage diabetes in children and pregnant women.

  • An overview of diabetes: Patients and their family members can get an overview of the disease and read about several emerging issues. This resource is provided by the National Institute of Diabetes and Digestive and Kidney Diseases.
  • Diabetes glossary: If you or a loved one has received a recent diagnosis of diabetes, have a look through this glossary from the CDC to understand some of the words and terms commonly used in discussing this disorder.
  • Diabetes resource: To learn about diabetes, have a look at this comprehensive online resource from the CDC. It covers questions about diabetes, statistics, and trends, related medical news, and educational articles for patients and professionals.
  • Guide to diabetes: Find out all about diabetes, its statistics, ongoing research, and related resources. The information is supplied by the government’s Department of Health and Human Services.

Symptoms and diagnosis

  • Diabetes symptoms: The national institute of Diabetes provides a basic list of symptoms that diabetic patients can expect. If you have been experiencing changes in your health, this list is worth consulting.
  • When to be concerned: Since diabetes symptoms are not always very distinct, the Mayo Clinic has prepared a guide to consult. It describes symptoms which manifest more strongly and suggests when to see a doctor.
  • Diagnosing diabetes: This link offers plenty of information to patients regarding the ways in which diabetes is diagnosed and managed.

Risk factors, prevention, and screening

  • Type 2 diabetes risk test: Just about anyone can benefit from the ADA’s virtual diabetes risk test. It only takes a couple of minutes to complete but can effectively point out an individual’s risk for the disease.
  • Lowering the risk of diabetes: You can learn more about type 2 diabetes from the NDIC website and find out how to reduce or eliminate your risk.
  • Preventing type 2 diabetes: Healthfinder.gov outlines simple but effective steps to prevent diabetes or delay it. Some of the steps are maintaining an active lifestyle and healthy diet and lowering cholesterol levels.
  • How to take control: The Mayo Clinic shares some great tips for diabetes prevention.
  • Diabetes prevention program (DPP): The NDIC discusses the results of a large multicenter study that indicate that type 2 diabetes is preventable through weight loss and physical activity.

Diabetes greatly increases the risk of stroke. Healthcare providers will learn what to do in the suspected stroke algorithm, but it is still important for everyone to recognize the signs and know the importance of acting immediately.

Disease management and treatment

  • What happens after diagnosis: People who have been diagnosed with diabetes can consult the National Diabetes Education Program (NDEP) through this link to learn how to manage it and prevent complications.
  • Managing diabetes: This Mayo Clinic article describes how diabetes requires many life changes for proper management. Examples of these are changes to one’s diet, activity levels, schedules, and medication.
  • Checking blood sugar levels: This is a detailed guide on checking blood sugar levels. It lists the supplies needed and describes how to perform the test.
  • Diabetes and holidays: During holidays and special festivals, it can be difficult to refrain from eating treats and sweet foods. The CDC discusses this issue and offers helpful tips to diabetics on how to manage on such occasions.
  • 4 steps to manage your diabetes for life.


  • Helping a loved one cope with diabetes: Learn how to help a loved one cope with their condition from this insightful article by the NDEP.
  • Living with diabetes: While many diabetics may feel alone after their diagnosis, it helps to hear about coping strategies from others with the same disease. This blog on the Mayo Clinic site discusses how to cope with diabetes and manage it successfully.
  • Stress and diabetes: Just as stress affects people on a regular basis, it can also affect diabetics. Unfortunately, however, it can further complicate their condition. Check this link to find out about the symptoms of stress and how to cope with it.
This page was written by on Jan 13, 2022.