The American Diabetes Association suggests that diabetics should call the doctor if they aren't sure how to care for themselves, or if they have these warning signs:

• If symptoms of illness, possibly including fever, have continued for a couple of days without improvement.
• If diarrhea or vomiting has continued for more than six hours.
• If there are moderate or large amounts of ketones in your urine.
• If, even after taking enough insulin to account for your illness, your blood sugar is 240 or higher before meals and stays there for more than 24 hours.
• If you have symptoms of ketoacidosis or dehydration, which may include chest pain, difficulty breathing, dry or cracked lips, and breath that smells like fruit.