HomeBookmark Info.comMake Info.com your HomepagePlugins Visit other Info sites:
Info.com - Your independent search platform...
You are here:  Health » Conditions and Diseases » Diabetes

Diabetes Diagnosis

Find out about the process of diabetes diagnosis.

Early diagnosis can make managing diabetes easier. [© Shutterstock, 2010]
© Shutterstock, 2010
Early diagnosis can make managing diabetes easier.

Diabetes Diagnosis

Awareness of diabetes symptoms and a proactive attitude towards health maintenance can lead to early diabetes diagnosis. Early diagnosis, in turn, makes treatment and management of the disease more productive and reduces the risk of damage to various parts of the body that could occur from unrestricted blood glucose levels. The National Diabetes Information Clearinghouse (NDIC) estimates there are 23.6 million diabetics in the United States. That equates to 7.8 percent of the population and, of that portion, the NDIC estimates that 24 percent, or 5.7 million, remain undiagnosed.

Glucose Testing for Diabetes Diagnosis

Blood glucose is the main energy resource available to the body. The body breaks down the carbohydrates from food into simple sugars, including glucose. Insulin is made by the pancreas as a response to glucose. If the pancreas is not properly producing insulin, as in type 1 diabetes, or if the cells do not properly use the insulin produced, as in type 2 diabetes, or a combination of these factors exists, as in gestational diabetes, glucose remains in the blood and results in higher than normal blood glucose levels. Therefore, diabetes can be diagnosed by taking a sample of blood and measuring the amount of glucose present. The glucose is measured in milligrams per deciliter of blood (mg/dL). The results of these tests will usually be divided into three categories:

  • Normal levels mean the body is processing glucose and insulin correctly
  • Pre-diabetes levels mean the body is not processing glucose normally but isn't impaired enough to be considered diabetes
  • Diabetes levels mean there is a significant problem with the way the body is using the glucose in the blood


According to the American Diabetes Association, pre-diabetics will likely develop type 2 diabetes within 10 years if no intervening steps are taken.

Fasting Plasma Glucose Test

The fasting plasma glucose test is performed after the patient has abstained from eating for at least eight hours before the test. It measures the baseline level of blood glucose when the body is not working to balance the glucose obtained from food. A blood sample is taken and the glucose level is measured. A level from 70 to 99 mg/dL is considered normal. If the results show 100 to 125 mg/dL of blood glucose, the diagnosis is considered to be pre-diabetes with impaired fasting glucose. Results showing 126 mg/dL or above on at least two testing occasions confirms a diabetes diagnosis.

Oral Glucose Tolerance Test Without Pregnancy

The oral glucose tolerance test measures how the body processes a specific amount of glucose. The patient fasts for eight hours before the test. A blood sample is drawn immediately before the test begins. The test involves 8 ounces of a solution containing 75 grams of glucose, waiting two hours and then drawing another sample of blood. A result of 139 mg/dL or below is considered normal. A level between 140 and 200 mg/dL is considered pre-diabetic. A result over 200 mg/dL on at least two occasions is considered diabetes.

Oral Glucose Tolerance Test During Pregnancy

Testing for gestational diabetes during pregnancy is done with a slightly different oral glucose tolerance test called a glucose challenge test. This test involves drinking 8 ounces of a solution containing 50 grams of glucose and measuring the blood glucose level an hour later. The threshold for this test differs from clinic to clinic. However, a limit of 130 to 140 mg/dL is the most common range. A pregnant woman who tests above this threshold is usually recommended to take a three-hour oral glucose tolerance test.

The follow-up test is similar to the oral glucose tolerance tests for non-pregnant people, except a 100 gram glucose solution is used and samples are taken at the beginning of the test and hourly over a three-hour period. If at least two of the four measurements are above theses threshold limits, the woman is considered to have gestational diabetes:

  • 95 mg/dL before drinking glucose
  • 180 mg/dL at a one-hour internal
  • 155 mg/dL at the two-hour interval
  • 140 mg/dL at the three-hour interval


According to the Mayo Clinic, most healthcare providers administer this screening test and any follow up testing between 24 and 28 weeks gestation. If the woman is considered high risk for gestational diabetes, the provider may screen earlier to ensure timely treatment for the mother and baby.

Related articles

Search the Web

Disclaimer: No information obtained from or via this site is intended to be a substitute for any medical advice, diagnosis, or treatment. If you believe you may be experiencing a medical emergency, then call for emergency medical help. If you are in the United States the number is 911. Further terms of use and disclaimers can be read by visiting Info.com’s Full Disclaimer.
You are here:  Health » Conditions and Diseases » Diabetes
Home   |   About   |   Media Comments   |   Legal & Privacy Policy   |   Tell a friend   |   Contact
Copyright © 2012 Info.com – All Rights Reserved.