- The clinical utilities of blood glucose levels are:
- As a screening test for people who are at a high risk of developing diabetes
- Morbid obesity
- First-degree relative with diabetes mellitus
- Ethnic groups at higher risk:
- African
- Asian
- Hispanic
- Native American
- Pacific Islander
- History of impaired fasting glucose or impaired glucose tolerance
- History of low HDL cholesterol (
35 mg/dL) or elevated triglycerides (
250 mg/dL) - Mothers with newborns of greater than 9 lbs
- Women with a history of gestational diabetes
- As an aid in the diagnosis of insulinoma
- To evaluate disorders of carbohydrate metabolism
- To detect hyperglycemia or hypoglycemia
- To monitor drug or diet therapy in patients with diabetes mellitus or metabolic syndrome
- Diabetes mellitus is a metabolic disorder characterized by hyperglycemia and abnormal protein, fat, and carbohydrate metabolism
- Type 1 Diabetes:
- Defect in insulin secretion
- Type 2 Diabetes:
- A defect in insulin action, or a combination of defects in secretion and action
- The American Diabetes Association’s (ADA) criteria for diagnosing Diabetes Mellitus include 3 possible methods to make the diagnosis:
- Any combination of the following findings or confirmation of any of the individual findings by repetition on a subsequent day:
- Symptoms of diabetes (e.g., polyuria, polydipsia, unexplained weight loss) in addition to a random glucose level 200-mg/dL (11.1 mmol/L).
- Fasting blood glucose 126 mg/dL (7.0 mmol/L), after a minimum of an 8-hour fast
- Glucose level 200 mg/dL (11.1 mmol/L) 2 hours after glucose challenge (GTT) with standardized 75 gram oral load of glucose
- The American Diabetes Association's (ADA) criteria for diagnosing "Impaired Glucose Tolerance" (IGT) or "Impaired Fasting Glucose" (IFG) include:
- Blood plasma glucose is 100-125 mg/dL or 5.6-6.9 mmol/L OR
- Glucose level 140 mg/dL (7.8 mmol/L) but 200 mg/dL (11.1 mmol/L) 2 hours after glucose challenge (GTT) with standardized 75 gram oral load of glucose
- Glucose levels and vitamin deficiencies:
- Hyperglycemia may cause vitamin C deficiency by inhibiting cellular uptake of ascorbate. This is because of the structural similarity between glucose and vitamin C.
* Note that any one of these items should be confirmed by repetition on a subsequent day; except in the case of unequivocal hyperglycemia. The Oral Glucose Challenge is not recommended routinely.
* IGT or IFG, if left untreated, is high risk to develop into type 2 diabetes within 10 years.
Additional information
- Interfering factors:
- Elevated urea levels (uremia) can lead to falsely elevated glucose levels
- Acetaminophen use can lead to falsely elevated test results when the testing technique is the glucose oxidase or hexokinase method
- Very high white blood cell counts can lead to falsely decreased glucose values
- Glycolysis due to failure to refrigerate sample or not sending it immediately to the laboratory may lead to falsely normal level
- Bacterial contamination of specimen
- Failure to separate clot from serum promptly
- Related laboratory tests include:
- Blood urea nitrogen
- C-Peptide
- Creatinine
- Fructosamine
- Glucose tolerance tests
- Glycated hemoglobin A1c
- Insulin
- Insulin antibodies
- Ketones
- Microalbumin
-2A