Type 2 Diabetes: Diagnosis

Also known as: Casual plasma glucose; random blood sugar test.

What is it? The random plasma glucose test measures plasma, or blood, glucose levels. It is performed with a small blood draw taken at any time of the day (hence the name "random").

Why is this test performed? Generally as a screening test for diabetes when a patient has had food or drink and therefore can't do a fasting plasma glucose test or oral glucose tolerance test.

How is this test performed? The test consists of a simple blood draw, which is sent to your doctor's lab for analysis.

What is the "normal" range for results? A random plasma glucose test that is under 200 mg/dl (11.1 mmol/l) is considered normal.

What do abnormal results mean? Levels of 200 mg/dl (11.1 mmol/l) or higher, along with the presence of symptoms of diabetes (e.g., excessive thirst and/or urination, blurry vision, unexplained weight loss), indicate a diagnosis of diabetes. The ADA recommends that the diagnosis be confirmed with a subsequent retest on a different day. The retest should be an oral glucose tolerance test or the fasting plasma glucose test if possible.

Other conditions which may result in an elevated result include pancreatitis, Cushing's syndrome, liver or kidney disease, eclampsia, and other acute illnesses such as sepsis and myocardial infarction (heart attack).

A lab result which measures below the normal range can indicate problems such as reactive hypoglycemia, renal or hepatic insufficiency, hypopituitarism, or malabsorption syndrome, and will usually require further diagnostic testing.