Many conditions affect the utilization of glucose in the body including, drugs, stress, illness, infection, insulin resistance and diabetes. Doctors employ blood glucose tests for screening and diagnosis of problems with glucose homeostasis, or equilibrium. The fasting blood glucose test, post-prandial blood glucose test and oral glucose tolerance test employ an enzyme assay and a meter to detect levels. The A1C test estimated an average blood glucose concentration over a two-month to three-month period.
Fasting Blood Glucose
For the fasting glucose test, a person is asked to fast for at least 12 hours. A lab then takes a blood sample and analyzes it for serum blood glucose content. Normal fasting blood glucose levels are under 100 mg per deciliter. The American Diabetes Association reports that fasting blood glucose levels between 100 mg/dl and 125 mg/dl indicate pre-diabetes. If they are above 125 mg/dl more than once, that indicates diabetes. Those who are pre-diabetic are at higher risk for developing type II diabetes and cardiovascular disease.
Post-prandial Glucose
In a post-prandial glucose test, labs measure blood glucose levels two hours after a person eats a meal. A 2005 study in "Clinical Therapeutics" reported that 33 percent of those diagnosed with type II diabetes had normal fasting blood glucose levels, but also had elevated post-prandial blood glucose levels. A study published in the January 2009 issue of "Current Vascular Pharmacology" reported that elevated post-prandial blood glucose levels in type II diabetics contribute significantly to the risk of cardiovascular disease. The International Diabetes Federation recommends post-prandial blood glucose levels in type II diabetics be kept below 145 mg/dl.
Oral Glucose Tolerance
An oral glucose tolerance test measures the response of the body to a rapid increase in blood glucose concentration. In this test, fasting individuals consume a drink containing 75 g of glucose. A technician will draw blood samples every 30 minutes or 60 minutes for two hours after the patient drinks the solution. The American Diabetes Association says that if the results are between 140 mg/dl and 200 mg/dl deciliter, a person does not have a normal tolerance to glucose. A blood glucose level of greater than 200 mg/dl indicates type II diabetes.
A1C
A1C, also known as hemoglobin A1c or HbA1c, refers to glucose modified hemoglobin. The amount of glucose modified hemoglobin in the blood at any one time is proportional to the average circulating glucose levels in the blood for 100 days to 120 days. A1C levels are reported as a percentage of the amount of hemoglobin protein that has been modified by glucose. A1C levels in healthy non-diabetic persons are between 4 percent and 5.9 percent. An article in the January 2009 issue of "Diabetes Care" notes that the American Diabetes Association recommends people with diabetes maintain A1C levels below 7 percent, while the guidelines of the International Diabetes Federation recommend a level below 6.5 percent.
Hypoglycemia
Monitoring blood glucose levels is critical not only for determining if blood glucose levels are elevated in type I or type II diabetes, but also for identifying low blood glucose levels, or hypoglycemia. A report in the April 2010 issue of "The Journal of the American Medical Association" noted that combining certain medications for the treatment of diabetes increases the number of hypoglycemic episodes. Hypoglycemia can be life-threatening.
References
- American Diabetes Association
- Pubmed.gov: "Clinical Therapeutics": Postprandial glucose regulation: new data and new implications
- Pubmed.gov: "Current Vascular Pharmacology": Postprandial glucose - a potential therapeutic target to reduce cardiovascular mortality
- International Diabetes Federation 2005: Global Guideline for Type II Diabetes
- "Diabetes Care"; Medical Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for the Initiation and Adjustment of Therapy; Oct.. 22, 2008
