Glucose Tolerance Test after 1 hour in serum

What is it? 

It is a blood test performed one hour after consuming a standard Glucose dose. It is most commonly used as part of the glucose tolerance test (GTT), which helps to evaluate how the body handles sugar – i.e., how the pancreas releases insulin and how cells respond to glucose. 

How is the test performed? 

The patient needs to drink a certain amount of glucose solution (usually 50 or 75 g), and after one hour, a blood sample is taken to determine glucose concentration. This test is often performed during pregnancy as a primary test to detect gestational diabetes. 

When is it recommended? 

• For pregnant women – during the 24–28 weeks of pregnancy; 
• When fasting glucose is normal, but there are symptoms (fatigue, thirst, frequent urination); 
• Suspecting prediabetes or metabolic syndrome. 

Benefits: 

The test allows identifying hidden carbohydrate metabolism disorders before diabetes symptoms become apparent. This is especially important for pregnant women, as gestational diabetes can affect fetal development and the course of childbirth. 

What is important to know? 

Usually, no special preparation is required before the test, but it is advised to avoid intense physical activity and stress on the day of the test. Sometimes this test is the first step – if results are elevated, an extended GTT with measurements after 2–3 hours may be recommended.