What is an oral glucose tolerance test?

This is an automatically translated article.

The article was professionally consulted by Doctor Pham Thi Mai Nhung - Obstetrician and Gynecologist - Department of Obstetrics and Gynecology - Vinmec Danang International General Hospital
Glucose tolerance test is a method used to diagnose diabetes, especially for pregnant women. Help detect gestational diabetes early, avoid complications affecting mother and baby may occur.

1. What is an oral glucose tolerance test?

The oral glucose tolerance test is a method used to measure the body's ability to use glucose, which is the body's main source of energy. The method can also be used to diagnose pre-diabetes and diabetes. Among them, the oral glucose tolerance test is commonly done to check for gestational diabetes.

2. When is the oral glucose tolerance test used?

This test is recommended by doctors for pregnant women in the case of gestational diabetes. In particular, glucose testing is recommended for pregnant women at 24-28 weeks of pregnancy.
In addition, for those with suspected or known risk factors for type 2 diabetes, this test is also recommended for those with suspected or known risk factors for diabetes. type 2 sugar in adults.
In addition, testing will be ordered for those who have a fasting blood sugar level higher than 126mg/dL or an HbA1c test greater than 6.5%.

3. How is the oral glucose tolerance test performed?

The procedure includes:
First, the doctor will take a blood sample to measure the fasting blood glucose level. This will provide a baseline for you to evaluate other glucose values ​​after the test. You will then be asked to use a certain amount of glucose between 75g or 100g of glucose. The doctor will then take blood samples 1, 2, or 3 hours apart after taking the glucose. The blood sample will be taken 30 minutes to 3 hours after you take the glucose. You can return to your usual activities after the test. Your doctor will tell you about your medical conditions and recommend effective treatment. Sometimes, doctors order additional tests. Always follow your doctor's instructions.

4. What are the precautions when performing an oral glucose tolerance test?

The following should be taken into account when conducting the test:
Glucose tolerance testing is contraindicated in patients with confirmed hyperglycemia who also have specific symptoms of hyperglycaemia or have 2 samples Fasting blood glucose > 7.0mmol/L, patients with acute illness, chronic malnutrition. Patients need to eat normally for 3 days before the test. Absolutely do not use corticosteroids, diuretics, beta-blockers for at least 3 days. The patient should rest for at least 30 minutes before the test. The glucose tolerance test will be performed in the morning after fasting for 10-14 hours. Take blood for a fasting blood sugar test, then give the patient 75g of glucose to drink for 5 minutes. Measure blood glucose at 1 and 2 hours after drinking sugar water. The point of note is that during the test, the patient can sit but not smoke or drink coffee. After taking an oral glucose tolerance test, you should eat a little when you feel dizzy or nauseous. Absolutely follow all instructions of the doctor, from exercise to diet.

5. Diabetes diagnosis results after glucose test

During the first prenatal visit:
If one of the fasting blood glucose values ​​is > 7.0mmol/L, HbA1c > 6.5%, or random blood glucose > 11.1 mmol/L, then the woman has diabetes. clinical route. If the fasting blood glucose is between 5.1 and 7.0mmol/L, the pregnant woman has gestational diabetes. If the fasting blood glucose is less than 5.1mmol/L, it is imperative to wait until the 24th to 28th week of pregnancy to have an oral glucose tolerance test to diagnose gestational diabetes. For visits between 24 and 28 weeks of pregnancy: diagnosis is based on fasting glucose (>5.1 mmol/L), 1 hour after oral glucose intake (> 10 mmol/L), and 2 hours later when taking glucose (> 8.5 mmol/L)
If fasting blood glucose > 7.0mmol/L, the pregnant woman has clinical diabetes. At the same time, if one or more of the parameters in Table 2 is greater than the above value, it is gestational diabetes. In normal pregnant women, all three parameters are smaller than the above values. Oral glucose tolerance testing is one of the routine techniques at Vinmec. This is a simple, easy to do, inexpensive and economical technique for the patient because the patient is completely outpatient. Glucose test helps to detect gestational diabetes very early for early consultation and treatment to prevent dangerous pregnancy complications such as stillbirth, premature delivery and high specificity.
The advantages of performing the Glucose test at Vinmec include:
Modern testing machine system and high accuracy. The team of doctors and nurses have extensive experience in the diagnosis and treatment of diseases. Automated biochemical testing machine system AU 680, AU 480 and very high accuracy. Glucose tolerance test applies to pregnant women from 24 to 28 weeks who have not been screened for gestational diabetes and impaired glucose tolerance.

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