If you experience symptoms of severe increased thirst, frequent urination, unexplained weight loss, increased hunger, tingling of your hands or feet -- your doctor may run a test for diabetes. This article discusses the various diabetes tests used to diagnose the condition.

According to the American Diabetes Association, 21 million children and adults in the United States, or 7% of the population, have diabetes today. Yet millions of Americans are unaware that they have diabetes because there may be no warning signs.

To confirm the diagnosis of type 2 diabetes, your doctor will order a fasting plasma glucose test or a casual plasma glucose.

Fasting Plasma Glucose Test

The fasting plasma glucose test (FPG) is the preferred method for diagnosing diabetes because it is easy to do, convenient, and less expensive than other tests, according to the American Diabetes Association.

How Do I Prepare for the Blood Glucose Test?

Before taking the blood glucose test, you will not be allowed to eat anything for at least 8 hours.

What Happens During the Blood Gluose Test?

During a blood glucose test, blood will be drawn and sent to a lab for analysis.

What Do the Results of the Blood Glucose Test Mean?

Normal fasting blood glucose is between 70 and 100 milligrams per deciliter or mg/dL for people who do not have diabetes. The standard diagnosis of diabetes is made when two separate blood tests show that your fasting blood glucose level is greater than or equal to 126 mg/dL.

However, if you have normal fasting blood glucose, but you have risk factors for diabetes or symptoms of diabetes, your doctor may decide to do a glucose tolerance test (see below) to be sure that you do not have diabetes.

Some people have a normal fasting blood glucose reading, but their blood glucose rapidly rises as they eat. These people may have glucose intolerance. If their blood glucose levels are high enough, they may be diagnosed with diabetes.

Casual Plasma Glucose Test for Diabetes

The casual plasma glucose test is another method of diagnosing diabetes. During the test, blood sugar is tested without regard to the time since the person's last meal. You are not required to abstain from eating prior to the test.

A glucose level greater than 200 mg/dL may indicate diabetes, especially if the test is repeated at a later time and shows similar results.

For more detail, see WebMD's article Blood Glucose and Diabetes.

Oral Glucose Tolerance Test for Diabetes

The oral glucose tolerance test is yet another method used to detect diabetes, but it is usually only done during pregnancy to diagnose gestational diabetes or for someone who is suspected of having type 2 diabetes yet has a normal fasting glucose level. It can also be performed to diagnose pre-diabetes.

For more detail, see WebMD's article Oral Glucose Tolerance Test.

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