The sugar in your blood, or blood glucose, is what provides you with the energy you need to survive. There are several different tests for blood sugar. Some are used to diagnose diabetes, while others are used to monitor diabetics' blood sugar levels. A "good" blood sugar level depends on the type of test being administered.
Fasting Blood Glucose
A fasting blood glucose measures your blood sugar level after a period of fasting, usually 8 hours, according to Lab Tests Online. A normal fasting blood glucose is defined as 70 to 99 mg/dL. If your fasting blood glucose falls between 100 and 125 mg/dL, it is considered impaired fasting blood glucose. A fasting blood glucose of 126 mg/dL or higher on more than one occasion usually indicates diabetes.
Oral Glucose Tolerance Test
The oral glucose tolerance test, or OGTT, measures your response to a liquid solution that contains 75 g of glucose. During this test, your doctor draws blood two hours after consumption of the glucose solution. A glucose level of less than 140 mg/dL is defined as normal glucose tolerance. If glucose levels fall between 140 and 200 mg/dL, they are considered impaired glucose tolerance. Levels over 200 mg/dL on more than one testing occasion usually indicate diabetes.
Hemoglobin A1c
The hemoglobin A1c, or Hb A1c, is used to track blood sugar levels in people who are known diabetics. The Hb A1c represents an average blood sugar over a period of three months, which can help your doctor determine how well your diabetes is controlled. An Hb A1c level of 6 to 7 percent is considered ideal, while an Hb A1c of 7 to 8 percent is considered low risk for complications. If your Hb A1c reaches 8 to 10 percent, it is considered high and indicates a moderate to high risk for diabetic complications. Hb A1c levels of higher than 10 percent are referred to as dangerously high.
Gestational Diabetes
Gestational diabetes is a form of the condition that occurs during pregnancy. There are two diagnostic tests for gestational diabetes. The first is called the glucose challenge test. During this test, a pregnant woman is asked to consume a glucose drink that contains 50 g of glucose. One hour after consumption of the drink, blood is drawn. A blood sugar level of less than 140 mg/dL is defined as normal. If blood sugar exceeds 140 mg/dL, another test called the gestational diabetes diagnostic, or OGTT, is performed.
During the OGTT, a blood sample is drawn one, two and three hours after ingestion of a 75 g or 100 g glucose drink. After one hour, blood sugar should be less than 180 mg/dL. After two hours, blood sugar should be less than 155 mg/dL, and the three-hour blood sugar should be less than 140 mg/dL. If a female's blood sugar level exceeds two or more of these values, she is diagnosed with gestational diabetes.
