TAGS
Overview
Blood glucose levels are used to diagnose or monitor diabetes. Several forms of diabetes exist: Type 1 diabetes, generally diagnosed in children and young adults, is characterized by the body’s inability to produce insulin. Type 2 diabetes is the most common form of diabetes and occurs when the body does not produce enough insulin or the cells are unable to use the insulin produced. Gestational diabetes, when present, usually develops at around 28 weeks of pregnancy due to inadequate insulin production and hormonal activity. This type of diabetes usually goes away after delivery, but is associated with an increased risk for type 2 diabetes later in life.
Fasting Blood Glucose
This test requires a patient to fast for at least 12 hours, after which time a blood sample is drawn. A normal fasting blood glucose level is below 100 mg/dl. Impaired fasting glucose, also known as pre-diabetes, is found at levels between 100 and 125 mg/dl. If the level is higher than 125 mg/dl, this is considered diabetes.
The National Diabetes Information Clearinghouse, or NDIC, defines pre-diabetes as “…blood glucose levels higher than normal, but not high enough for a diagnosis of diabetes.” Many pre-diabetics will go on to develop type 2 diabetes within 10 years. However, with physical activity, weight loss and healthy diet, type 2 diabetes may be delayed or prevented.
Oral Glucose Tolerance Test
The oral glucose tolerance test is the most common test used. According to the American Diabetes Association, blood glucose is tested after fasting, then a second time two hours after consuming a glucose-rich drink. A normal blood glucose level two hours after drinking the glucose drink is less than 140 mg/dl. Impaired glucose tolerance, a type of pre-diabetes, is diagnosed between 140 and 199 mg/dl. Diabetes is considered 200 mg/dl or higher.
Casual Plasma Glucose Test
A casual, or random, glucose test is a blood test taken at any time–fasting is not required. A result of 200 mg/dl indicates that a patient may have diabetes, but a definite diagnosis must be confirmed by another test.
A1C Testing
A1C testing is recommended by the American Diabetes Association, or ADA, as a new diagnostic tool for diabetes. This test–also known as glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C or HbA1c–is traditionally used to monitor how blood glucose levels are being controlled in diabetics over time, up to three months. The A1C test is a simple blood test that measures the percentage of hemoglobin, the protein in red blood cells that carries oxygen that is coated by sugar. The higher the percentage, the poorer the blood glucose control. According to the American Diabetes Association, pre-diabetes is confirmed at 5.7 to 6.4 percent A1C while diabetes is identified by an A1C of 6.5 percent or greater. Those without diabetes have A1C levels around 5 percent. The test is faster and easier–no fasting, drinking or waiting is required.
Monitoring
For those already diagnosed with diabetes and monitoring blood glucose levels on a glucometer, numbers and results may vary. Glucose levels depend on the type of diabetes and where a patient’s doctor would like the numbers to be at fasting, before eating, after eating and before bed. The American Diabetes Association defines glycemic control in nonpregnant adults with diabetes as 70 to 130 mg/dl before a meal and less than 180 mg/dl after a meal. A reading of less than 70 mg/dl indicates hypoglycemia and should be treated quickly.
Diet, stress, illness and activity are all factors that affect blood glucose levels. Doctors, dietitians and certified diabetes educators can educate and individualize plans for those diagnosed with pre-diabetes, diabetes type 1 or 2, or gestational diabetes.
Mandy Seay, RD, LD, CDE
.
