Determine if you're a candidate for diabetes testing by considering the risk factors and the symptoms. Most of these risk factors and symptoms hold true for people age 45 and over, but they're being seen more often in obese people under age 40 and especially in obese teens. Also testing should be done on adults who have a family history of diabetes.
The most common Type 2 diabetes risk factors for people over age 45 include a history of the disease within immediate family members, a sedentary lifestyle, a blood pressure reading of 140/90 or higher (or already being treated for high blood pressure), cardiovascular disease, a triglyceride level over 250 mg/dL and an HDL (good cholesterol) level below 35 mg/dL. Non-caucasians are more prone to developing diabetes as are women who were diagnosed with gestational diabetes or who delivered a baby weighing more than 9 pounds.
Type 1 (juvenile) diabetes is usually diagnosed in children or teens, and can develop within just a few weeks, unlike Type 2 which develops over a period of time and with age. Because young people generally haven't developed some of the illnesses that older people have (those in danger of developing Type 2), any youth showing symptoms of diabetes should be tested for the disease.
Symptoms of diabetes include excessive thirst, increased urination, fatigue, increased appetite, unexplained weight loss and blurred vision. Other symptoms more likely present in adults (Type 2 diabetics) are tingling or pain in the hands or bottom of the feet, infections of the toenails or feet (similar to athlete's foot or foot fungus) that won't clear up, or having cuts or other injuries that are slow to heal. A symptom specifically in young people is thrush or a similar infection, or an irritation of the genitals.
Visit your doctor for a fasting plasma glucose (FPG) test. ("Fasting" means you refrain from eating or drinking anything but water, black coffee or unsweetened tea for eight hours prior to the blood test.) Your doctor will look at a variety of factors from this blood test, including the glucose level, cholesterol and levels of enzymes in the liver and kidneys, as both these organs are affected by diabetes.
If your FPG reading is 99 or below, you probably don't need further testing at this time.
A reading of 100 to 125 indicates pre-diabetes, meaning you are at greater risk of developing diabetes. Your doctor will suggest you change some day-to-day activities such as increasing exercise, watching your diet and losing a modest amount of weight; these steps can help you stave off full-blown diabetes.
An FPG level of 126 means you are diabetic; your doctor may want to repeat the same test on another day to confirm this. Or if the number is high enough, if you were pre-diabetic earlier, or are showing symptoms, he may want to move on to the next test in his arsenal, the oral glucose tolerance test (OGTT).
Make an appointment to have the three-hour OGTT test. You'll need to fast prior to this test.
Your doctor or her nurse will test your blood glucose level (most likely with a simple finger-prick test) at the beginning of your appointment. You'll then drink a glucose beverage and sit for about two hours before someone tests your blood again.
A level of 139 or below is normal, a reading of 140 to 199 indicates pre-diabetes, and 200 or higher indicates diabetes.
Pregnant women undergo the OGTT to determine gestational diabetes. However, their glucose levels are tested four times with high (diabetic) levels being 95 or higher fasting, 180 or higher after one hour, 155 or higher after two hours, and 140 or higher after three hours.