When a child is evaluated for diabetes, the physician considers several factors. Diabetes diagnosis often includes the following:
Physicians ask parents and caregivers whether diabetes runs in the child's family. They also ask about the child's history of symptoms and his or her lifestyle. For example: Has the child been losing weight? Is he/she overweight? Is he/she tired most of the time? Is he/she thirstier than usual or urinating more often? Does he/she eat healthy meals? Does he/she exercise regularly? Is he/she irritable? Is he/she having trouble seeing the board at school?
During the physical exam, the physician measures the child's weight and blood pressure. He or she checks for infections and/or wounds that are not healing properly and looks for visible signs of diabetes, such as acanthosis nigricans (dark, thick, soft areas of skin).
If diabetes is suspected, the physician often begins by checking the child's glucose level in a urine sample. However, the level of glucose in the blood is necessary to confirm the diagnosis of diabetes. Diabetes is diagnosed if the child's blood glucose level is 300 mg/dL (milligrams/deciliter) or above in a random whole-blood glucose test.
In a fasting test (i.e., after not having eaten for at least 8 hours), a blood glucose level of 200 mg/dL or higher confirms diabetes. If the child does not have symptoms of diabetes, physicians usually take blood glucose tests on different days to be sure. Children who have symptoms caused by diabetes usually have fasting blood glucose levels of 250 mg/dL or higher.
Differential Diagnosis of Diabetes in Children
Several conditions can cause symptoms similar to diabetes and must be ruled out. These conditions include the following:
- Diabetes insipidus (frequent urination and excessive thirst may signal problems with the hormone ADH [anti-diuretic hormone]; e.g., either the pituitary gland does not produce enough ADH or the kidneys do not respond to it correctly)
- Hyperthyroidism (condition in which the thyroid gland produces too much of a hormone)
- Renal glucosuria (condition in which a problem in the kidneys causes excessive amounts of glucose in the urine, even when blood glucose levels are normal or low)
- Pheochromocytoma (adrenal gland tumor)
- Salicylate toxicity (poisoning by a salt or salicylic acid; e.g., aspirin poisoning)
If a diagnosis of type 2 diabetes seems likely, physicians also perform diagnostic tests to determine if the child has type 1 diabetes.