Should I test my urine for glucose and ketones?

Dr. Jack Merendino, MD
Endocrinology Diabetes & Metabolism
Finding glucose in the urine of someone who has not yet been diagnosed will sometimes be a tip-off that they have developed diabetes, but glucose doesn’t appear in the urine unless the blood sugar is around 240 or even higher for many people, so there is no real reason to test the urine for sugar because it isn’t helpful in managing your diabetes if all you know is that you are roughly under 240. On the other hand, ketones in the urine is a sign that you may be getting seriously ill. Routine monitoring of ketones isn’t necessary, but it should be done if you feel sick, especially if you have type 1 diabetes. If you have diabetes and there are ketones in your urine, it’s time to contact your healthcare provider.  
Diabetes experts don't recommend testing your urine for glucose because this method is not as accurate as checking your blood. But testing your urine for ketones can be very important in managing your diabetes. Check with your doctor to see if you need to monitor your ketone levels. You may need to do ketone urine checks if your blood glucose is more than 300 milligrams per deciliter (mg/dL) or if you're sick with the flu, a cold or a stomach bug. If you are having symptoms of high ketones -- feeling tired all the time, thirst or dry mouth, flushed skin, mental confusion, difficulty breathing or a fruity smell on your breath -- it can be a good idea to check your ketone levels.
Urine testing is not an accurate way to measure blood glucose. It is the way to check for ketones when you cannot eat or are ill. A buildup of ketones tells you that you are developing ketoacidosis. Ketones are breakdown products of fat that produce acid in the body. Too much acid can result in you being hospitalized. Therefore, when you are sick with a cold or the flu, you should test your urine for ketones and call your health care team if you detect any. You can buy urine ketone testing strips at the drugstore.
The information about blood glucose that you get from urine testing for glucose is not precise enough to make decisions for treatment. Your kidney does not spill glucose into your urine until your blood glucose is higher than 200 mg/dl. The ADA does not recommend that you use urine glucose testing (especially if you're taking insulin) if you can perform fingerstick blood glucose testing.

Continue Learning about Diabetes


Diabetes mellitus (MEL-ih-tus), often referred to as diabetes, is characterized by high blood glucose (sugar) levels that result from the body’s inability to produce enough insulin and/or effectively utilize the insulin. Diabetes ...

is a serious, life-long condition and the sixth leading cause of death in the United States. Diabetes is a disorder of metabolism (the body's way of digesting food and converting it into energy). There are three forms of diabetes. Type 1 diabetes is an autoimmune disease that accounts for five- to 10-percent of all diagnosed cases of diabetes. Type 2 diabetes may account for 90- to 95-percent of all diagnosed cases. The third type of diabetes occurs in pregnancy and is referred to as gestational diabetes. Left untreated, gestational diabetes can cause health issues for pregnant women and their babies. People with diabetes can take preventive steps to control this disease and decrease the risk of further complications.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.