Adults who are at elevated risk for diabetes should have their blood sugar level measured at least every three to five years. That includes people with a personal history of heart attack, stroke, or heart disease, as well as those with any of these coronary-risk factors: a systolic (upper) blood pressure over 135 mmHg or a diastolic (lower) pressure over 80 mmHg; obesity (with a body mass index of 30 or over); or an LDL (bad) cholesterol over 130 mg/dL. Adults without those risks should also consider screening, though the benefits for them are less certain.
Early symptoms. You should also be tested if you have early symptoms of diabetes, listed below:
- Extreme thirst
- Extreme hunger
- Frequent urination
- Sores or bruises that heal slowly
- Dry, itchy skin
- Unexplained weight loss
- Blurry vision that changes from day to day
- Unusual tiredness or drowsiness
- Tingling or numbness in the hands or feet
- Frequent or recurring skin, gum, bladder, or vaginal yeast infections
How to test. The gold standard is the oral glucose tolerance test, in which patients drink a sugar solution and have their blood sugar checked several times over the next two hours. But nearly as good and faster is the fasting blood glucose test. For it to be accurate, avoid nonessential drugs and all food and drink, except water, for 9 to 12 hours before. Another test, the hemoglobin A1c, reflects the average blood sugar level over the previous three months. Though some doctors now use it for screening, we think it should be limited to monitoring blood sugar control in people already diagnosed with diabetes.
If you've been told you have diabetes, talk with your doctor about monitoring your blood sugar level at home. And see our Ratings to find the best blood glucose meter.