Type 1 diabetes is a chronic medical condition in which the body’s immune system attacks and destroys the insulin-producing beta cells of the pancreas. This results in a reduced ability of the body to produce insulin, which is needed to regulate blood glucose levels. The diagnosis of type 1 diabetes is made by looking for certain signs and symptoms, as well as through laboratory tests.
The most common signs and symptoms of type 1 diabetes are increased thirst, frequent urination, extreme hunger, unexplained weight loss, fatigue, irritability, and blurred vision. If these symptoms are present, a doctor may order a blood test to check for elevated levels of glucose in the blood. If the results of this test are abnormal, additional laboratory tests may be ordered to confirm the diagnosis.
These tests include a test to measure the amount of a particular type of antibody in the blood, known as anti-GAD antibodies. This test looks for the presence of antibodies that are associated with type 1 diabetes, and is often used as a screening tool for the condition. Other tests used to diagnose type 1 diabetes include measurements of fasting glucose and C-peptide levels. Fasting glucose levels measure the amount of glucose in the blood after an 8-hour fast, while C-peptide levels measure the amount of insulin still being produced by the body.
The doctor may also order an oral glucose tolerance test, in which the patient drinks a sugary liquid and blood glucose levels are measured before and 2 hours after drinking the liquid. If the results of this test are abnormal, type 1 diabetes is usually diagnosed.
In some cases, a doctor may order additional tests to rule out other conditions that can cause similar symptoms, such as celiac disease, autoimmune thyroiditis, and other forms of diabetes. Once the diagnosis of type 1 diabetes has been made, treatment can begin. Treatment usually consists of lifestyle changes, as well as insulin therapy.