- a blood glucose level of 200 mg/dl or above at any time of the day without regard to the time of the last meal
- a blood glucose level of 126 mg/dl or above after no food or drink for at least 8 hours
Type 1 Diabetes
A Answers (4)
The most common way to diagnose diabetes in children and non-pregnant adults is through blood tests. These tests measure milligrams of blood sugar per deciliter, which is expressed by mg/dL. One test, the fasting blood glucose test, is usually performed after an eight-hour fast. If this test reveals a blood glucose level of 126 mg/dL or higher, diabetes is present. A random blood glucose test, taken at any time of the day, indicating a blood glucose level of 200 mg/dL or higher also confirms diabetes, especially when accompanied by symptoms. Another test, called the oral glucose tolerance test, which is conducted two hours after drinking 75 grams of glucose dissolved in water, that results in a blood glucose level of 200 mg/dL or higher is an indication of diabetes.
Medical experts now recommend a newer test, the glycated hemoglobin (A1C) test, to diagnose type 1 diabetes. The A1C test will measure average blood sugar level over a longer period of time. Certain conditions such as pregnancy can make these tests unreliable, so it is important to ask your doctor about which test is the right one for you.
Some people--especially children, teenagers and young adults--are not diagnosed with type 1 diabetes until they are admitted to a hospital for diabetic ketoacidosis (DKA). This life-threatening condition occurs when ketones, or fatty acids, are produced as the body burns fat and muscle instead of glucose for fuel. DKA develops in people who have type 1 diabetes (and some people who have type 2 diabetes) when their blood sugar is very high. During hospitalization, people with DKA are watched closely and receive tests to measure the levels of electrolytes and sugar (glucose) in their blood.
If a person is not in ketoacidosis, the American Diabetes Association's criteria for symptoms, a medical history, a physical exam, and blood tests are used to diagnose type 1 diabetes. These blood tests include:
Other tests that may suggest diabetes
You may need a thyroid-stimulating hormone (TSH) test when type 1 diabetes is diagnosed and then every 1 to 2 years. This test checks for thyroid problems, which are common among people with diabetes. Neither a home blood sugar test nor a urine test for sugar is recommended to screen for or diagnose diabetes.
Screening for type 1 diabetes is not recommended by the American Diabetes Association. Such screening would include testing everyone for islet cell antibodies. This test can show if a person is more likely to get type 1 diabetes.
People who are found to have islet cell antibodies may be able to participate in studies about preventing type 1 diabetes. These people need to be referred to a medical center conducting a type 1 diabetes prevention study.
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