HomeHealthHealthGlycemic curve: what it is, what it is for and reference values

Glycemic curve: what it is, what it is for and reference values

The glycemic curve exam, also called oral glucose tolerance test, or OTG, is an exam that may be ordered by the physician in order to aid in the diagnosis of diabetes, prediabetes, insulin resistance or other changes related to pancreatic cells.

This test is performed based on the analysis of fasting blood glucose concentration and after ingestion of a sugary liquid provided by the laboratory. Thus, the doctor can assess how the body functions in the face of high concentrations of glucose. OTG is an important test during pregnancy, being included in the list of prenatal tests, as gestational diabetes can pose a risk to both the mother and the baby.

This test is usually ordered when fasting blood glucose is altered and the doctor needs to assess the person’s risk of having diabetes. As for pregnant women, if fasting blood glucose is between 85 and 91 mg/dl, it is recommended to do the OTT around 24 to 28 weeks of pregnancy and investigate the risk of diabetes during pregnancy. Learn more about risk

Glycemic curve reference values

The interpretation of blood glucose values ​​after 8 hours of fasting are:

Fasting blood glucose value
Normal Less than 100 mg/dL
decreased tolerance Between 100 and 125 mg/dL
Diabetes Equal to or greater than 126 mg/dL

The interpretation of the glycemic curve 2 hours after drinking the sugary liquid is as follows:

Blood glucose value in 120 minutes
Normal 140 mg/dL
decreased tolerance Between 140 and 199 mg/dL
Diabetes Equal to or greater than 200 mg/dL

In the previous tables, only values ​​are mentioned when fasting and after 120 minutes of drinking the drink, as these are the most relevant results to aid in the diagnosis of pre-diabetes and diabetes.

When the result is impaired glucose tolerance, it means that there is a high risk of developing diabetes, which can be considered pre-diabetes. In addition, only one sample from this test is not sufficient for the diagnosis of the disease, and fasting blood glucose should be collected on another day to confirm it.

If you think you may have diabetes, better understand the symptoms and treatment of diabetes mellitus.

How is the exam taken

The exam is performed with the aim of verifying how the body reacts to high concentrations of glucose. For this, the first blood collection must be done with the patient fasting for at least 8 hours. After the first collection, the patient must drink a sugary liquid that contains about 75 g of glucose, in the case of adults, or 1.75 g of glucose for each kilogram of the child.

After consumption of the liquid, some collections are made in accordance with the doctor’s recommendation. Normally, 3 blood collections are performed until 2 hours after drinking the drink, that is, collections are performed before drinking the liquid and 60 and 120 minutes after drinking the liquid. In some cases, the doctor may request more dosages until the 2 hours of liquid consumption are completed.

The collected samples are sent to the laboratory, where analyzes are carried out in order to identify the amount of sugar in the blood. The result can be released in the form of a graph, indicating the amount of glucose in the blood at each moment, which allows a more direct view of the case, or in the form of individual results, with the doctor having to make the graph to assess the health condition of the patient.

Oral glucose tolerance test in pregnancy

The OTG exam is essential for pregnant women, as it allows the risk of gestational diabetes to be checked. The exam is performed in the same way, that is, the woman needs to fast for at least 8 hours and, after the first collection, she must drink the sugary liquid so that the dosages can be made according to the medical recommendation.

Collections should be made with the woman lying down comfortably to avoid discomfort, dizziness and falling from her own height, for example. The reference values ​​of the OTG test in pregnant women are different and the test must be repeated if any changes are observed.

This exam is important during prenatal care, and is recommended to be performed between the 24th and 28th week of gestational age, and aims to make an early diagnosis of type 2 diabetes and gestational diabetes. High blood glucose levels during pregnancy can be dangerous for both the woman and the baby, with premature birth and neonatal hypoglycemia, for example.

Understand better how the symptoms, risks and how the diet should be in gestational diabetes.

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