Diabetes is diagnosed by testing the blood for sugar levels. Blood is tested in the morning after you have fasted overnight.
Typically, the body keeps blood sugar levels between 70 and 100 milligrams per deciliter (mg/dL), even after fasting. If a blood sugar level after fasting is greater than 125 mg/dL, diabetes is diagnosed.
Your doctor will examine you to look for signs of diabetes complications. These include:
Obesity, especially abdominal obesity.
High blood pressure
Deposits of blood, or puffy yellow spots in the retina of your eyes
Decreased sensation in the legs
Weak pulses in the feet
Abnormal pulses in the abdomen
Blisters, ulcers or infections of the feet
Laboratory tests are also used routinely to evaluate diabetes. These include:
Fasting glucose. A test of your blood sugar level after you have not eaten for several hours.
Hemoglobin A1C (HbA1c). Indicates how close to average your blood glucose has been during the previous two months.
Blood creatinine and urine microalbumin. Tests for evidence of kidney disease.
Lipid profile. Measures levels of triglycerides and total, HDL, and LDL cholesterol. This evaluates the risk of atherosclerosis.