What is Diabetes, How is it Diagnosed and What are its Types?

14/04/2026
Obesity

What is Diabetes, How is it Diagnosed and What are its Types?

Diabetes (diabetes mellitus), widely known as the disease of our age, is a metabolic disorder characterized by chronically high levels of glucose (sugar) in the blood. It occurs as a result of a deficiency or ineffectiveness of the insulin hormone secreted by the pancreas, which is the body's insulin producer.

Today, diabetes is one of the most common chronic diseases worldwide, and when early diagnosis and proper management are not provided, it can lead to serious complications such as heart disease, kidney failure, and vision loss.

What is Diabetes?

Diabetes essentially develops when the body cannot use glucose properly. Normally, the insulin hormone ensures energy production by carrying sugar in the blood to the cells. However, in diabetes, either no insulin is produced or the produced insulin does not work effectively. In this case, glucose accumulates in the blood, and hyperglycemia occurs.

How is Diabetes Diagnosed?

Diabetes is diagnosed based on specific laboratory tests and clinical findings. The most commonly used diagnostic criteria are:

A Fasting Blood Sugar (FBS) level ≥ 126 mg/dL confirms a diagnosis of diabetes. A minimum of 8 hours of fasting is required for the measurement.

An Oral Glucose Tolerance Test (OGTT) level ≥ 200 mg/dL at the 2nd hour after ingesting 75 grams of glucose is an indicator of diabetes.

An HbA1c (Glycated Hemoglobin) level ≥ 6.5%, which shows the average blood sugar level over the last 2-3 months, is an indicator of diabetes.

A Random Blood Sugar level ≥ 200 mg/dL combined with classic symptoms (thirst, frequent urination) is diagnostic.

Clinically, usually at least one of these tests being positive is sufficient for a diagnosis.

Prediabetes (Prediabetic Period)

Before diabetes develops, there is an intermediate period called "prediabetes." In this period, the fasting blood sugar is 100–125 mg/dL, and the HbA1c is 5.7–6.4%. This stage is a critical period where diabetes can be prevented with early intervention.

What Are the Types of Diabetes?

Diabetes is basically divided into 4 main groups:

Type 1 Diabetes: It is an autoimmune disease. The pancreas does not produce insulin. It usually appears in childhood or at a young age.

Type 2 Diabetes: It is the most common type of diabetes. There is insulin resistance and a relative insulin deficiency. It is strongly associated with obesity and lifestyle.

Gestational Diabetes (Pregnancy Diabetes): It appears during pregnancy. It can pose risks for the mother and baby. It usually resolves after birth but increases the risk of Type 2 diabetes in the future.

Other Specific Types of Diabetes: Genetic causes, diseases of the pancreas and diabetes that develops due to medications can be reasons.

Early Diagnosis Is Important

Diabetes is a disease that can be kept under control with early diagnosis and proper management, but can lead to serious complications if neglected. Blood sugar measurements and the HbA1c test play a critical role in the diagnostic process.

It is of great importance that individuals, especially those in the risk group, undergo regular screening for the prevention and control of diabetes.

Resources