1. About what percentage of Americans have type 2 diabetes?

A. Too low. About 8 percent of Americans have type 2 diabetes, although almost one-quarter of them don't know it, presumably because they haven't had their blood sugar tested. About three-quarters of our survey respondents guessed too high. Perhaps they were thinking of prediabetes, the borderline high blood sugar that affects at least one-quarter of Americans.

B. You're right. But almost one-quarter of the people with diabetes don't know it, presumably because they haven't had their blood sugar tested. About three-quarters of our survey respondents guessed too high. Perhaps they were thinking of prediabetes, the borderline high blood sugar that affects at least one-quarter of Americans.

C. Too high. About 8 percent of Americans have type 2 diabetes, although almost one-quarter of them don't know it, presumably because they haven't had their blood sugar tested. Like you, about three-quarters of our survey respondents overshot this number. Perhaps they were thinking of prediabetes, the borderline high blood sugar that affects at least one-quarter of Americans.

D. Too high. About 8 percent of Americans have type 2 diabetes, although almost one-quarter of them don't know it, presumably because they haven't had their blood sugar tested. Like you, about three-quarters of our survey respondents overshot this number. Perhaps they were thinking of prediabetes, the borderline high blood sugar that affects at least one-quarter of Americans.

2. About what age should a healthy adult start having his or her blood sugar tested?

Too young. Our experts recommend getting tested every three years, starting at age 45. However, you should start earlier if you experience symptoms or are overweight and have an additional diabetes risk factor.

Too young. Our experts recommend getting tested every three years starting at age 45. However, you should start earlier if you are experience symptoms or are overweight and have an additional diabetes risk factor.

On the nose. Our experts recommend getting tested every three years starting at age 45, earlier if you experience symptoms or are overweight and have an additional diabetes risk factor.

That's late. Our experts recommend getting tested every three years starting at age 45, earlier if you experience symptoms or are overweight and have an additional diabetes risk factor.

3. A person is diagnosed with diabetes when his or her fasting blood sugar repeatedly reaches what level?

Too low. But don't feel bad; only about one-third of our respondents chose the correct answer, 126 milligrams per deciliter. People with readings between 100 and 125 milligrams per deciliter are widely considered to have prediabetes and are at very high risk of developing the full-blown disease.

Too low. But don't feel bad; only about one-third of our respondents chose the correct answer, 126 milligrams per deciliter. People with readings between 100 and 125 milligrams per deciliter are widely considered to have prediabetes and are at very high risk of developing the full-blown disease.

Good job! Only about one-third of our respondents got this right. People with readings between 100 and 125 milligrams per deciliter are widely considered to have prediabetes and are at very high risk of developing the full-blown disease.

Sorry, but no. Like a lot of our respondents, you guessed too high. Only about one-third of our respondents chose the correct answer, 126 milligrams per deciliter. People with readings between 100 and 125 milligrams per deciliter are widely considered to have prediabetes and are at very high risk of developing the full-blown disease.

4. Which of the following symptoms of diabetes is NOT common?

You're wrong. Fatigue is a symptom. Other telltale signs are frequent urination, especially at night, unexplained weight loss, and slow wound healing. (More symptoms to be aware of include tingling and numbness in the feet, blurry vision, frequent infections, and increased thirst.) Dizziness is not a common symptom.

You're right. Dizziness is not a common symptom. Telltale signs of diabetes are fatigue, frequent urination, especially at night, unexplained weight loss, and slow wound healing. (Other symptoms to be aware of include tingling and numbness in the feet, blurry vision, frequent infections, and increased thirst.)

You're wrong. Frequent urination is a symptom. Other telltale signs are fatigue, unexplained weight loss, and slow wound healing. (Other symptoms to be aware of include tingling and numbness in the feet, blurry vision, frequent infections, and increased thirst.) Dizziness is not a common symptom.

You're wrong. Unexplained weight loss is a symptom. Other telltale signs are fatigue, frequent urination, especially at night, and slow wound healing. (Other symptoms to be aware of include tingling and numbness in the feet, blurry vision, frequent infections, and increased thirst.) Dizziness is not a common symptom.

You're wrong. Slow wound healing is a symptom. Other telltale signs are fatigue, frequent urination, especially at night, and unexplained weight loss. (Other symptoms to be aware of include tingling and numbness in the feet, blurry vision, frequent infections, and increased thirst.) Dizziness is not a common symptom.

5. Which is NOT a health problem caused by diabetes?

You're wrong. Uncontrolled high blood sugar does contribute to cardiovascular problems. About a third of our survey respondents knew this. However, many did not know that diabetes can also cause nervous- system damage, dental disease, and kidney problems. Other health troubles caused by diabetes include vision problems (including blindness) and sexual dysfunction. But diabetes does not cause lung cancer.

You're wrong. Diabetes can cause nervous-system damage. Many of our survey respondents didn't know that, along with the fact that it can lead to dental disease and kidney problems. However, many did know about the increased risk of cardiovascular problems. Other health troubles caused by diabetes include vision problems (including blindness) and sexual dysfunction. But diabetes does not cause lung cancer.

You're right. Diabetes does not cause lung cancer (although it was difficult for us to come up with a health problem not linked to diabetes). Many of our survey respondents knew that diabetes can lead to cardiovascular complications. However, many did not know that it can also cause nervous-system damage, dental disease, and kidney problems. Other health troubles caused by diabetes include vision problems (including blindness) and sexual dysfunction.

You're wrong. Diabetes can lead to dental disease. Many of our survey respondents did not know that diabetes can also cause nervous-system damage or kidney problems. However, many did know that uncontrolled high blood sugar can lead to cardiovascular problems. Other health troubles caused by diabetes include vision problems (including blindness) and sexual dysfunction. But diabetes does not cause lung cancer.

You're wrong. Diabetes can lead to kidney problems. Many of our survey respondents did not know that diabetes can also cause nervous-system damage and dental disease. However, many did know that uncontrolled high blood sugar can lead to cardiovascular problems. Other health troubles caused by diabetes include vision problems (including blindness) and sexual dysfunction. But diabetes does not cause lung cancer.