Testing & Diagnosis for Type 1 Diabetes in Children

At Children’s Hospital Boston, we know that the first step in treating your child is forming an accurate and complete diagnosis.

Your child’s extreme thirst and frequent urination can often be a clue. To confirm a diagnosis, her doctor may order blood and urine tests including:

  • glycated hemoglobin (A1C) test: This blood test indicates average blood sugar level for the past two to three months.

  • random blood sugar test: A blood sample is taken at a random time.

  • fasting blood sugar test: A blood sample is taken after an overnight fast.

  • To distinguish between type 1 and type 2 diabetes, your child’s doctor may also check for autoantibodies in the blood that are common in type 1 diabetes.

  • Boston Children’s diabetes team also tests for the presence of ketones (byproducts from the breakdown of fat in children without enough insulin) in the urine or blood. When present, ketones also suggest that the child has type 1 diabetes.

Since test results should be confirmed with a second test on a different day, it’s likely that your child will have blood drawn more than once.

Is it diabetes?

Your child will be diagnosed with diabetes if her:

  • blood glucose is higher than 126 mg/dL first thing in the morning before eating or drinking for at least eight hours


  • blood glucose is greater than 200 mg/dL (more than once) after a meal or snack