Diagnosis
Fasting and Random blood glucose level : A overnight fasting blood glucose level of 125 mg/dl or higher and/or a random blood glucose level of 200 mg/dl or greater at any time of the day, along with diabetic symptoms, is sufficient to make the diagnosis of diabetes.
Hemoglobin A1C (glycohemoglobin) : This test measures the average glucose level over the prior two to three months. Normal levels are below 5.7 percent, and a result between 5.7 and 6.4 percent is considered prediabetes. Diabetes is diagnosed if the hemoglobin A1C level is 6.5% percent or higher.
C-peptide level : It is a useful and widely used measure for assessing pancreatic beta cell function. C-peptide is produced in equimolar amounts to endogenous insulin and is a direct measure of insulin secretion by the body.
C-peptide levels are used to differentiate between type 1 and type 2 diabetes.
C-peptide level of less than 0.2 ng/ml is associated with a diagnosis of type 1 diabetes mellitus (T1DM), in which pancreatic insulin secretion is insufficient or absent.
In contrast, C-peptide level of 0.2 ng/ml or higher are typically seen in type 2 diabetes, in which insulin is produced in sufficient quantity but insulin resistance is seen.
The American Diabetes Association recommends routine screening for type 2 diabetes beginning at age 45, especially if you're overweight. If the results are normal, repeat the test every three years.
Screening is also recommended for people who are under 45 years of age and overweight in the presence of other risk factors such as heart disease, sedentary lifestyle, family history of type 2 diabetes, a personal history of gestational diabetes or blood pressure above 140/90 mm Hg.
