What Are Ketones, and Why Are They Important to Diabetes Self-Management?

All blood tests are tools. Some are to diagnose diabetes, some are to help you manage your diabetes on a daily or long term basis and some are to keep you safe.

People with diabetes are told about blood testing and how important testing is to manage their blood glucose. It is a critical part of diabetes management. Whether it is done in the physician’s office or the patient’s home it is an invaluable tool, Unfortunately a very important test, ketone testing is often not taught or taught only to people with type 1 diabetes. This test can be life saving and should be part of every person with diabetes knowledge and skills. It is simple and if you have diabetes you should know about it.

What Are Ketones?

When the body is unable to burn glucose it burns fat and this produces a chemical called ketones. This occurs when there is too little insulin for the amount of glucose in the body. Possible causes for this could be:

  • Experiencing stress or illness such as fever,
  •  Having an infection.
  • Omitting or taking too little insulin
  • Eating more food than planned
  • Improper storage of insulin

If left untreated, ketones continue to rise and can result in a condition called Diabetic Ketoacidosis, or DKA. This condition is quite serious and requires immediate medical attention. DKA is the most common cause of hospitalization and death among children and young adults with diabetes, and the leading cause of adverse events for insulin pump users.

Why Measure Blood Ketones?

Studies suggest that most, if not all emergency department and hospital admissions beyond initial diabetes diagnosis could be prevented if people better managed their diabetes care and knew the warning signs when ketoacidosis was developing. Blood ketone testing provides a rapid, accurate, and early warning sign that ketones are rising and that your body is out of balance. By knowing this, steps can be taken at home to prevent DKA and avoid trips to the hospital.

A study done in a New York Hospital showed that if DKA was prevented at home it could save $250 for a physician visit, $2,500 for an emergency department visit, and approximately $25,000 for a hospital or intensive care admission. There are lots of people without health insurance and this could be a terrible burden for them. No one wants a visit or admission to the hospital if it can be prevented. It is always traumatic and frightening, and simple management can prevent DKA from occurring.

Who Should Test for Ketones?

It is very important that every person with type 1 diabetes test for ketones, especially children, young adults, and people who are on insulin pumps. More than two thirds of DKA episodes occur in people with type 1 diabetes. These people get multiple insulin injections a day and often have high blood glucose, known as hyperglycemia, and low blood glucose, known as hypoglycemia. When dealing with insulin pumps there are many things that can drastically alter blood sugars such as pump failure or something as simple as a disconnect. Pumps are a very effective tool in managing diabetes and are being used by many more people that in the past.

Pregnant women with gestational diabetes or pre-existing diabetes should know that their condition can be complicated as DKA occurs more frequently and rapidly with them than in other people. Since DKA is so dangerous for children, ketone testing should never be neglected. It is such an important tool to use in protecting children at home and at school. Unfortunately not enough information is given to the type 2 patient about testing for ketones. Because it has not been considered urgent for this group of people, it is often neglected and healthcare providers many times do not stress the importance of protecting oneself from DKA. It is very important that all people with diabetes or parents of children with diabetes be ready to check their ketone levels whenever their blood glucose levels are higher than 250 and whenever they are sick.

Which Is Better, Blood or Urine Testing?

Until recently urine testing was the only test for ketones and it was not always reliable. A patient could have a blood glucose level over 250 and still not “spill” ketones into the urine. People who had difficulty urinating could not get a sample to test and getting a child to “pee on the stick” is not very practical. Urine strips must be stored properly or they can give false negative readings. Another important fact is that people with type 2 were not often taught in class to test or even what the test meant.

The blood test measures the ketone that is actually causing DKA. By measuring blood ketones, you get a “right-now” measurement where urine ketone numbers can be delayed several hours making the blood test more accurate.

A finger stick blood sample is also more easily obtained than a urine sample for measuring ketones. Finally, blood tests give you an actual number unlike urine strips that require you to compare the color on the test strip to a color chart.


How to Test for Blood Ketones

Recently blood glucose meters were developed that allow you to test for ketones in your blood as well. You can test your blood with the strips for glucose and then switch the strip and test for ketones using the same fingerstick. What really is helpful is that the strips are individually wrapped and good for two years so you do not waste them and end up being much cheaper than throwing away a jar of unused urine strips. This is an important new development and it is hoped that it will reduce the incidence of DKA.

Urine ketone testing is still available and is an alternative for someone who chooses not to test their blood for ketones. Ketostix strips are available and it is a simple dip stick that you put into urine and then compare the color of the strip to the color chart on the bottle. Be careful to not bend the strip, keep the lid on the strips tightly and review it in good light. Urine strips can go bad quickly and give you incorrect readings when they go bad. They should not be kept in a bathroom medicine cabinet where moisture can effectaffect them.
Why and where should you test for ketones?

You may then ask why test at all. Ketone testing shows that you are in balance and that your body is working well under stress. We diabetes educators talk about Sick Days all the time and the reality is that everyone gets sick sometimes. I am not talking about “diabetes sick” but the things that occur with everyone. Colds and flu or upset stomachs can mess up your system enough to start ketone development. If you cannot eat or keep food down you have no glucose to use for energy so your body starts to burn fat. While it is true that you can have elevated blood glucose and not develop ketones, each person is different. Some people will develop ketones with blood glucose of 250 or less and for others it will take blood glucose of 500. That is why glucose and ketone testing go hand and hand.

The American Diabetes Association recommends that you test for ketones:

If your blood glucose is above 250mg/dl; If you have an injury, infection, illness, fever, cold, nausea, vomiting, or diarrhea, or abdominal pain, or you have symptoms of DKA. If DKA is not treated it can lead to dehydration, confusion, coma and even death.

I have seen patients in each of these conditions and it can be very frightening for the patients and their families. One patient became so confused and frightened that he picked up a television and threw it at the staff. He had to be restrained and sedated. After the episode he had no memory of what had occurred. You and your health care provider should decide when it is right for you to test in order to meet your needs and give you the information both of you need to keep you well.

Rules for Sick Day Management

Sick day management is very important and here are some basic rules:

  • Test your blood glucose and ketones every 4 hours
  • Try to keep yourself well hydrated. Drink 8 ounces of water every hour if you can keep the fluid down
  • Notify your health care provider if you vomit for more than two hours as there is medication you may be given to stop the nausea or vomiting.
  • Ask about continuing your oral medication or reducing your insulin dosage based on your blood glucose testing
  • To avoid low blood glucose, hypoglycemia, try and sip small amount of regular soda, ginger ale may help, of juice that is half juice and half water.
  • Make sure that someone knows you are ill and keeps in contact with you throughout the event.


What Are the Symptoms of DKA?

Extreme thirst, frequent urination, fruity smell to breath, agitation, irritation or aggression, confusion , general weakness or sluggishness, fatigue, rapid breathing, fast heart beat and a feeling of being ill

What You Should Do About Blood Ketone Test Results

When you test it is important that you know what the test means and what action you should take.

In blood testing, the guideline on the package of test strips will tell you what action to take, depending on your ketone numbers:

  • Blood ketone reads less than 0.6 or meter reads “Lo,” no action is required. If you are sick, monitor for changes. ü You should check every 4 hours, both blood and ketones.
  • Blood Ketone reads 0.6 to 1.5, you may be developing a problem. Ask your healthcare provider if s/he wants to be called when these numbers appear.
  • Blood Ketone reads 1.5-3.0 and is accompanied by high blood glucose, contact your health care provider immediately.
  • Blood Ketone reads 3.0 or higher, contract your healthcare provider immediately. If you cannot reach your provider, go to the emergency department of a hospital.


In urine testing, if the reading is negative, no action is required. If “small or trace” reading, drink fluids, take your medications as ordered and test again in four hours. For readings of “moderate or large”, contact your healthcare provider. If you get a “large” reading on retest and your blood glucose is elevated, contact your healthcare provider again. If you are unable to reach your provider, go to the emergency department of a hospital.



Ketone testing is an important part of keeping you safe and should not be forgotten or neglected. Discuss with your health care provider how ketone testing fits into your diabetes management. If Ketone Testing is not included in your Diabetes Self Management Education Program or by your health care provider make sure you ask about it.


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