DIFFERENTIAL DIAGNOSIS
- Type 1 diabetes mellitus
- Other specific types of diabetes mellitus
– Genetic defects of β -cell function
– Genetic defects in insulin action
– Diseases of exocrine pancreas
– Endocrinopathies
– Drug or chemical induced (see below)
– Infections
– Immune mediated
– Genetic syndromes sometimes associated with diabetes
– Hemochromatosis
- Gestational diabetes mellitus
LABORATORY
- Criteria for diagnosis; any one is sufficient
– Symptoms of diabetes (polyuria, polydipsia, weight loss) plus casual (random) plasma glucose – 200 mg/dL (11.1 mmol/L)
– Fasting plasma glucose ≥ 126 mg/dL (7.0 mmol/L) on 2 occasions
– 2 hour plasma glucose ≥ 200 mg/dL (11.1 mmol/L) during OGTT with 75 g glucose load
Drugs that may alter lab results:
- Pentamidine
- Nicotinic acid
- Glucocorticoids
- Thyroid hormone
- Diazoxide
- Beta adrenergic agonists
- Thiazides
- Dilantin
- Alpha-interferon
- Some fluoroquinolones
- Some second generation (atypical) antipsychotics
Disorders that may alter lab results: See Differential Diagnosis
PATHOLOGICAL FINDINGS N/A
SPECIAL TESTS
- Glucose tolerance test usually not necessary, except when diagnosing gestational diabetes
- Hemoglobin A1C not recommended for diagnosis, but helpful in management
IMAGING N/A
DIAGNOSTIC PROCEDURES N/A
