Of course, only a health care provider can make an accurate diagnosis of diabetes. A trip to the doctor is the next logical step if you or someone you love has symptoms of diabetes or you run a risk of developing diabetes.
Glucose Tests
Although you or your health care provider may suspect that you have diabetes because of your symptoms, the only sure way to tell is with glucose tests.
Diabetes causes your blood glucose levels to be above normal some or all of the time. Your blood glucose levels may be high even though you haven’t eaten recently. So, checking the amount of glucose in your blood can determine whether you have diabetes or not. There are four types of tests used to diagnose diabetes: A1C test, fasting plasma glucose test, random plasma glucose test, and two-hour oral glucose tolerance test.
Plasma glucose tests measure the amount of glucose in the plasma of your blood to determine whether the level is higher than normal. Plasma glucose is different from whole-blood glucose, which contains blood cells. In the laboratory, your blood sample is spun in a machine to remove blood cells, platelets, and cell debris. Only the plasma is left. Scientists measure the amount of glucose in the plasma, and these numbers can be 15% higher than whole-blood readings.
A1C Test
• The A1C test can be used to diagnose diabetes.
• Blood is collected from a fingerstick or vein.
• A1C values represent average blood glucose levels over the past 2–3 months.
• The test measures the concentration of hemoglobin molecules that have glucose attached to them. The measure is given as a percentage. An 8% level means that 8% of your molecules are glycated (sugar coated).
• An A1C of 6.5% or higher is used to diagnose diabetes.
Fasting Plasma Glucose Test
• In diabetes, extra glucose remains in the blood, even after fasting.
• For this test, you will be asked not to eat or drink anything but water for at least 8–10 hours. Then, a sample of your blood is taken and the amount of glucose in the blood is measured.
• For those without diabetes, the amount of glucose after fasting is usually less than 100 mg/dl.
• However, when the amount of fasting plasma glucose is 126 mg/dl or higher, diabetes is suspected. A firm diagnosis of diabetes is made when two fasting plasma glucose tests, done on different days, are at least 126 mg/dl.
Random Plasma Glucose Test
• The simplest way to detect diabetes.
• This test measures the amount of plasma glucose at any given time and is done without fasting.
• You may be diagnosed with diabetes if your plasma glucose is 200 mg/dl or higher and you have obvious symptoms, such as frequent urination, intense thirst, blurred vision, unexplained weight loss, and extreme tiredness.
Oral Glucose Tolerance Test
• This test can also be used to diagnose diabetes.
• For this test, you will be asked not to eat or drink anything overnight. Then, in the morning, a sample of your blood is taken before and two hours after you have a drink that contains glucose.
• If your fasting plasma glucose is 126 mg/dl or higher and/or your post-drink plasma glucose is 200 mg/dl or higher, then you will be diagnosed with diabetes regardless of your symptoms.
Categories of Increased Risk for Diabetes
Sometimes increased risk for diabetes is apparent before diabetes develops. If your fasting plasma glucose test is greater than 100 mg/dl but less than 126 mg/dl, you may have impaired fasting glucose. Some people also have impaired glucose tolerance, a condition in which blood plasma glucose levels are higher than normal (140 mg/dl to 199 mg/dl) 2 hours after the start of an oral glucose tolerance test. If your A1C is 5.7–6.4%, you may be at similar risk.
If you have impaired fasting glucose and/or impaired glucose tolerance, you may be diagnosed with prediabetes. This is not the same as having diabetes, but it sometimes occurs before diabetes develops.
If you have been diagnosed with prediabetes, you will want to have your blood glucose tested routinely and watch for symptoms of diabetes. Also, you need to talk with your health care provider about reducing your risk of heart disease. Keeping your weight in the healthy range and exercising regularly will lower your chances of developing diabetes.
Prediabetes
Some people with prediabetes never get diabetes, especially if they make lifestyle changes that help improve their health, such as exercising more, making healthier food choices, and losing some unwanted weight. However, some of the same problems that result from having diabetes also occur in people with prediabetes.
Which Type of Diabetes?
If tests reveal that you have diabetes (and you’re not pregnant), the next question is whether you have type 1, type 2, or another type of diabetes. Although the symptoms and blood test results can be similar for both type 1 and type 2 diabetes, the causes are very different.
Part II
Types of Diabetes
CHAPTER 3
Type 1 Diabetes
Now, that you’ve brushed up on some of the basics of diabetes and glucose, you’re probably wondering about your specific type of diabetes. In this chapter, you’ll find out all about type 1 diabetes.
Type 1 diabetes used to be called juvenile diabetes. Half of all people with type 1 diabetes are diagnosed during childhood or their early teen years.
As you know, being diagnosed with diabetes can be a scary—no matter how old you are when you find out. However, being diagnosed with type 1 diabetes as a child can be downright terrifying. For example, it might have come on so fast that you went into a coma before anyone suspected diabetes. After asthma, type 1 diabetes is the second most common chronic disease in children.
Keep in mind, type 1 diabetes can occur at any age. About 5% of adults with diabetes have type 1 diabetes.
Early Symptoms and Tests
People with type 1 diabetes make very little or no insulin, which means that the symptoms of diabetes are often serious and swift. Without insulin, the cells in your body can’t do their essential work. Most people with type 1 diabetes will feel quite sick and may even be rushed to the hospital due to high blood glucose.
Common Symptoms of Type 1 Diabetes
• Frequent urination as the body tries to flush out excess glucose in the blood
• Extreme thirst due to dehydration
• Fatigue because the necessary glucose is not getting to your cells
• Blurred vision because of a buildup of fluid in your eyes or elevated glucose levels
• Weight loss, even with increased appetite
• Nausea and vomiting
A Different Type 1 Diabetes
Some