Inmates with any of the following should be evaluated for diabetes: symptoms of hyperglycemia, symptoms that may represent complications of diabetes, or clinical presentations that include diabetes in the differential diagnosis. The American Diabetes Association (ADA) criteria for the diagnosis of diabetes in nonpregnant adults are shown in Table 1 (next page). The diagnostic cut-points recommended by the ADA are based on fasting plasma glucose values. Fasting serum glucose values run 10–15% lower than fasting plasma glucose values. The BOP recommends fasting serum glucose tests for initial screening and diagnosis. A fasting plasma glucose test should be obtained when fasting serum glucose values are borderline high, or if a patient has impaired glucose tolerance (IFG or IGT). (The BOP recommends the routine use of serum glucose testing because it does not require the special collection methods used in plasma glucose testing, i.e., a separate gray-top tube containing glycolytic inhibitor.)

The oral glucose tolerance test (OGTT) is not recommended for routine clinical use; however, it may be required when evaluating patients with impaired fasting glucose (IFG), or when diabetes is suspected despite a normal fasting plasma glucose test (as with postpartum evaluation of women with GDM). Unless unequivocal symptoms of hyperglycemia are present, diagnosis of diabetes requires that test results be confirmed by repeating the test on a subsequent day. The hemoglobin A1C should not be used for diagnostic purposes. “Pre-diabetes” is a new term applied to hyperglycemia that does not meet the diagnostic criteria for diabetes, i.e., impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Both IFG and IGT are associated with a high risk for diabetes and cardiovascular disease.
- Diagnostic criteria for diabetes and pre-diabetes (non-pregnant adults)

Normal
Fasting plasma glucose <100 mg/dl or
Oral glucose tolerance test (OGTT) 2-hr plasma glucose <140 mg/dl

Pre-diabetes
Impaired fasting glucose (IFG) = fasting plasma glucose of 100–125 mg/dl or
Impaired glucose tolerance (IGT) = OGTT 2-hr plasma glucose of 140–199 mg/dl

Diabetes
1. Symptoms of diabetes and a casual plasma glucose >200 mg/dl. “Casual” is defined as any time of day, without regard to the time since the last meal. The classic symptoms of diabetes include polyuria, polydipsia, and unexplained weight loss.
or
2. Fasting plasma glucose >126 mg/dl. Fasting is defined as no caloric intake for at least eight hours.
or
3. 2-h plasma glucose >200 mg/dl during an oral glucose tolerance test. The test should be performed using a glucose load containing the equivalent of 75-g anhydrous glucose dissolved in water.

Notes:
Serum glucose values run 10–15% lower than plasma glucose values. The BOP recommends the use of serum glucose testing for initial screening and diagnosis. When fasting serum glucose values are borderline high, or for patients with impaired glucose tolerance (IFG or IGT), a fasting plasma glucose should be obtained. To diagnose diabetes, lab results must be confirmed on a second test performed on a subsequent day (unless there are unequivocal symptoms of hyperglycemia).