When the body has no insulin, it's forced to burn fat for fuel. This produces ketones, and when they build up, the result can be a dangerous condition called diabetic ketoacidosis
It's scary, but it's important to know about: If left untreated, diabetic ketoacidosis (DKA) can lead to severe illness or even death. Protect yourself if you suspect DKA by testing for ketones. Since the body quickly tries to flush out accumulating ketones, they can be detected by testing the urine.
Who should test? People with type 1 diabetes whose blood glucose level goes above 240 mg/dl should test for ketones. If you have any type of diabetes and are sick, stressed, pregnant, or have blood glucose levels above 300 mg/dl, you should also perform a ketone test.
How often should I test? While your blood glucose reading will guide you in knowing when to test, you should be familiar with the symptoms of ketoacidosis so you can do a urine test if you suspect you have the condition. Indicators include frequent urination, thirst, rapid breathing, nausea, vomiting, shortness of breath, fatigue, a fruity smell to your breath, muscle aches or stiffness, and confusion. Pregnant women with diabetes should check for ketones every morning before breakfast or as directed by their doctor.
How do I test? Ketone tests are available at your pharmacy, so talk to your doctor about them as well as record-keeping methods he or she recommends. Most include either packages of strips or foil-wrapped strips (which store longer). Follow the instructions for using the test strips. The strips are placed in the urine stream or in a cup of collected urine; the liquid will react to the strip and through a color change will show the level of present ketones.
What do the results mean? Though each kit will have its own method of reading your ketone levels, all use a change of color to indicate the presence of ketones. Some may present you with a concrete quantity of ketones (such as 5 mg/dl or 20 mg/dl) while others may describe ketones as "trace," "small," or "large."