When is an ogtt performed

In some cases, infection after your procedure is possible. It's important to eat and drink normally in the days leading up to the glucose tolerance test. Let your doctor know if you're ill or taking any medications, as these factors can affect the results of your test. For eight hours before the test, you won't be able to eat or drink anything.

You might want to fast overnight and schedule the test for early the following morning. The glucose tolerance test is done in several steps. When you arrive at your doctor's office or lab, a member of your health care team will take a sample of blood from a vein in your arm. This blood sample will be used to measure your fasting blood glucose level. The American College of Obstetricians and Gynecologists recommends performing a one-hour blood glucose challenge test to screen for gestational diabetes in low-risk pregnant women between 24 and 28 weeks of pregnancy.

Your doctor may recommend earlier screening if you're at increased risk of developing gestational diabetes. Risk factors may include:. If your doctor determines you're at risk or you have a suspicious value on the one-hour test, you may be advised to take a three-hour glucose tolerance test. Survival radiology for GPs. Basic and advanced cardiac life support. Oral glucose tolerance testing. Thermal burns. Assessment and acute management in the general practice setting. Up front Keeping it simple.

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You cannot eat during the test. Serious side effects from this test are very uncommon. With the blood test, some people feel nauseated, sweaty, lightheaded, or may even feel short of breath or faint after drinking the glucose. Tell your health care provider if you have a history of these symptoms related to blood tests or medical procedures.

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Glucose is the sugar the body uses for energy. People with untreated diabetes have high blood glucose levels.

Glucose tolerance tests are also used to diagnose diabetes. Abnormal glucose tolerance blood sugar goes too high during the glucose challenge is an earlier sign of diabetes than an abnormal fasting glucose. Normal blood values for a 75 gram OGTT used to check for type 2 diabetes in those who are not pregnant:.

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. You may be instructed to stop taking certain medicines before the test. How It Is Done Glucose tolerance diagnostic test On the day of testing, the following steps will be done: A blood sample will be collected when you arrive.

This is your fasting blood glucose value. It provides a baseline for comparing other glucose values.

You will be asked to drink a sweet liquid containing a measured amount of glucose. It is best to drink the liquid quickly.

For the standard glucose tolerance test, you will drink 75 grams or grams. Pregnant women drink 50 grams of glucose. Blood samples will be collected at timed intervals of 1, 2, and sometimes 3 hours after you drink the glucose. Blood samples may also be taken as soon as 30 minutes to more than 3 hours after you drink the glucose. Blood test The health professional taking a sample of your blood will: Wrap an elastic band around your upper arm to stop the flow of blood.

This makes the veins below the band larger so it is easier to put a needle into the vein. Clean the needle site with alcohol. Put the needle into the vein. More than one needle stick may be needed. Attach a tube to the needle to fill it with blood. Remove the band from your arm when enough blood is collected.

Apply a gauze pad or cotton ball over the needle site as the needle is removed. Put pressure on the site and then put on a bandage. How It Feels You may find it hard to drink the extremely sweet glucose liquid. Risks Some people's blood glucose levels drop very low toward the end of the test. You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.

In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily. Results The oral glucose tolerance test OGTT measures the body's ability to use a type of sugar, called glucose, that is the body's main source of energy.