Scrabble pieces spelling KETONES

What are ketones? How do they relate to diabetes? How and when should I check for ketones? 

One of the most important things you do when you have diabetes, especially for people living with type 1 diabetes, is check your blood sugar. If you have been living with diabetes for a while, you have most likely developed a routine that is second nature to you. If you are newly diagnosed, you are learning how to manage your diabetes. You have or are developing a network to support you that includes your healthcare provider, support group(s), and diabetes supply companies like Diathrive. With your health care provider’s and others’ support, you can live a healthy life with diabetes. 

Sometimes, though, things can get out of whack. Things like illness, changes in diet, missing insulin doses, or changes in your body can create a situation where you are not getting enough insulin. If this happens, your body can start building up ketones in your urine and blood, which can be dangerous.

So, what are ketones anyway?   

What Are Ketones?

Ketones are a natural byproduct produced when your body burns fat for fuel (energy). Normally, your body produces energy by processing food into glucose and other nutrients that are absorbed into your bloodstream from your intestine. Glucose needs help getting into your cells and insulin is the hormone that allows cells to accept glucose where it is used for fuel. If this is all working properly, your ketone levels will not be a problem. 

If insulin and glucose are not available for fuel, your body burns fat instead. Sound like it might be a good thing? It depends on the situation. You can think of ketones like a back-up generator, allowing your body to function when glucose is not available or accessible as a source of fuel.  

Ketones in small amounts aren’t bad, and it’s normal to have a small amount of ketones in your body. People who are trying to lose weight often limit carbohydrates or skip meals which forces the body to burn fat for fuel. This is what is happening when someone is on a keto diet. In this situation, although you have enough insulin, you don’t have enough glucose available to fuel your cells. Because glucose is not available, your body burns fat instead for fuel. This normally isn’t a problem for people who don’t have diabetes.   

People living with diabetes, however -- particularly those living with type 1 diabetes -- do not have enough insulin to process glucose into fuel. This means that glucose is not accessible to your body as a fuel source. You may have enough (or too much) glucose in your blood, but without insulin it is not accessible to your cells. The result is the same as when glucose is not available -- your body starts burning fat instead. Small amounts of ketones are flushed from the body when you urinate, which is why you can test ketones in urine, but if you don’t have enough insulin to process glucose, ketone production can speed up and potentially build up to dangerous levels. Elevated levels of ketones can mean you have very high blood sugar.

If insulin levels remain too low, ketones build up in your system creating a condition known as diabetic ketoacidosis (DKA). If ketone levels go too high, it can be life-threatening. Diabetic ketoacidosis is more common in people living with type 1 diabetes, but it can also happen to a small percentage of people with type 2 diabetes. This is because people living with type 2 diabetes still produce insulin (at least at first), so the small percentage of those with very little insulin production are at higher risk of developing DKA. Production of insulin is one of the key differences between type 1 and type 2 diabetes. 

About Ketoacidosis

Diabetic ketoacidosis is a life-threatening condition that happens when the amount of ketones in urine and blood become so high as to be toxic. When ketone levels rise, your body tries to filter them out through your urine. Eventually your kidneys cannot keep up and ketone levels in your blood build up. DKA can lead to coma and even death. 

High levels of ketones often mean you also have high blood sugar levels too. Moderate ketone levels can be cleared on their own. Drinking water helps flush ketones from your system in conjunction with taking insulin to reduce blood sugar levels. Moderate to high levels of ketones must be corrected and can be caused by skipping insulin injections, if an insulin pump fails and the wearer is not aware of it, or when you are sick or do not inject enough insulin for the stress of illness. 

The most common causes of diabetic ketoacidosis are undiagnosed type 1 diabetes, lack of insulin, and illness. 

When Should You Be Testing for Ketones?

So how do you know if you need to test your urine for ketones? 

Ultimately, your health care provider will guide you on when to test, but there are several situations where people living with diabetes should test their urine for ketones:

  • Your blood sugar is higher than 300 mg/dL. If your blood sugar is high, you should check your blood sugar and ketone levels every 4 to 6 hours.

  • You feel tired most of the time.

  • You are often thirsty or tired.

  • You have abdominal pain, feel nauseous, are vomiting, or have diarrhea.

  • You are ill with a cold or the flu, or have an infection.

  • Your skin is dry or red.

  • You have difficulty breathing or shortness of breath.

  • Your breath has a fruity smell.

  • You feel disoriented, confused, or in a fog.

  • You stop eating carbohydrates like rice and bread, or have been fasting.

  • You are pregnant and have been diagnosed with gestational diabetes.

  • You drink alcohol in excess. 

Because strenuous exercise, some medications, and diet (like low-carb diets) can affect the results of a ketone test, ask your health care provider if there are foods or medicines (including nonprescription medicines like herbs, vitamins, and supplements) you should avoid before taking the test. 

How to Check Ketone Levels  

You can test for ketones in urine or blood. Testing for ketones in urine is easy because it does not require a blood sample. All you have to do is collect urine in a bowl or cup, dip the end of a test strip into the urine, and wait for the results. You can also hold the test strip under your urine stream instead of collecting urine in a cup or bowl. 

Some ketone testing strips give results in numbers and others give results through a color change on the test strip. If the test strip gives number results, compare the number on your test strip to the guidelines on the box. Consult your healthcare provider regarding what your normal range should be. 

If the ketone strip is the kind that changes color, the color will change depending on how many ketones are in your urine. Make sure you read the instructions for your ketone test strips, but generally there are four possible color results, all corresponding to the amount of ketones in your urine. The color of the test strip will change depending on the level of ketones in your urine. 

Results indicate amount of ketones in the urine: 

  • None

  • Trace 

  • Moderate

  • Large 

You should keep track of your ketone amounts over time, the same way you do when you test blood sugar. One way to do this is to record ketone readings in your logbook along with blood sugar numbers, especially since ketones will usually coincide with high blood sugar. Slightly high levels of ketones could mean that ketones have started to rise in your body. You may have missed in an insulin shot, or other factors may be making your ketones rise. 

It’s best to check your blood sugar and give yourself an insulin injection if needed. Drink water to help flush the ketones out of your system, and do not exercise if you have high blood sugar and high ketones. Although exercise is good to help bring down high blood sugar, it is not good if you have high levels of ketones because it might make your blood sugar go even higher. You should test for ketones again in a few hours and contact your healthcare provider if the levels continue to rise.  

If the result of the ketone test indicates a moderate or large amount of ketones, contact your healthcare provider. Moderate to high levels of ketones may mean you have diabetic ketoacidosis.  If you cannot contact your health care provider immediately go to an emergency room or urgent care facility. 

In Summary

You should be aware of the signs of high ketone levels. If your diabetes is not well managed, if you miss insulin doses, or if there are changes in your health like an illness or a diet change, you could be at greater risk for diabetic ketoacidosis. 

Knowing the signs of high ketone levels can alert you to the need for a ketone test of your urine. Instead of thinking of the ketone test as just another test, think of it as a tool in your toolbox for living a healthy life with diabetes. 


American Diabetes Association. 2019. Five Things to Know About Ketones

MedlinePlus. 2020. Ketones in Urine

WebMD. 2020. What Are Ketones and Their Tests?

Mayo Clinic. 2020. Diabetic Ketoacidosis 

Diabetes Research Institute. 2019. Ketones: What you Need to Know 

American Diabetes Association. Type 1 Diabetes Overview

University of California, SF, Diabetes Education Online. Ketones 

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