Knowledge base
What does OGTT mean?
The oral glucose tolerance test (also known as OGTT) is used to screen for diabetes that does not yet cause symptoms, as well as prediabetic conditions (impaired glucose tolerance, insulin resistance) and gestational diabetes.

What does the oral glucose tolerance test show, and why is it important to perform it?
In Hungary today, 68% of the adult population is overweight or obese, which poses a significant risk for type 2 diabetes and cardiovascular diseases.
The treatment of the disease and its complications places a heavy burden on the patient, their family, the healthcare system, and society as a whole. In Hungary, even 15 years ago, the annual cost of treating diabetes complications was 17 billion forints, with the total societal cost nearing 100 billion forints. This is why it is crucial to detect the disease as early as possible. According to the results of a recent representative survey in Hungary, the prevalence of diabetes in the 20-69 age group is 7.5%, but without screening, half of the cases go undetected. Yet, diabetes diagnosed at the age of 40 can result in a loss of 10-15 years of quality life!
Pregnancy
Another important population at risk for diabetes is pregnant women. Diabetes diagnosed during pregnancy is known as gestational diabetes (GDM). The method for screening GDM is the OGTT test, conducted between the 24th and 28th weeks of pregnancy. According to data from Hungarian centers, the prevalence of GDM is 5-10%. Moreover, 50% of mothers with GDM develop “true” diabetes within 5 years after childbirth!

Carbohydrate metabolism disorder
Carbohydrate metabolism disorders that precede manifest diabetes—such as impaired fasting glucose (IFG) and impaired glucose tolerance (IGT)—also pose a significant cardiovascular risk. According to international data, the prevalence of IFG in the adult population averages between 4.8-7.6%, while the prevalence of IGT ranges from 3-9%. Screening experiences show that for every known diabetic, there is one undiagnosed diabetic individual. Applying this international data to the Hungarian population, approximately 1-1.5 million people in Hungary are diabetic, and there is an almost equal number of individuals in the early stages of carbohydrate metabolism disorders (prediabetics). A study involving a population of seventy thousand people aged 20-70 (FINDRISC Hungary) revealed that 7.6% of high-risk individuals who were previously unaware of their carbohydrate metabolism disorder (!) were already manifest diabetics at the time of the study, 14.08% had IFG, and an astonishing 24.79% had IGT. In 46% of the participants who underwent the oral glucose tolerance test, a previously undiagnosed carbohydrate metabolism disorder was found!
Screening large populations would aid in the early detection of carbohydrate metabolism disorders. In cases of slightly elevated fasting blood glucose levels (≥5.6 mmol/l), it is already recommended to perform a 75 g glucose OGTT.

When is it recommended to perform an oral glucose tolerance test (OGTT)?
To rule out gestational diabetes, the OGTT should be performed between the 24th and 28th weeks of pregnancy in all cases or based on the attending physician’s instructions.
For individuals with a family history of carbohydrate metabolism disorders, such as diabetes or insulin resistance.
At the discretion of the attending physician, the test is recommended in any case where a carbohydrate metabolism disorder is suspected, based on the following symptoms and complaints:
– Weight loss or gain
– Increased thirst
– Frequent sugar cravings during the day
– Irregular menstruation
– PCOS (polycystic ovary syndrome)
– Difficulty conceiving
– Extreme mood swings, fatigue, and concentration issues related to meals
– Abnormal fasting blood glucose levels
– Slow wound healing
– Excessive urination
– Suspected insulin resistance
It is also essential for monitoring the treatment of an already diagnosed condition.