Ketone Levels: Where Should I Be and How Can I Check?

Ketones are chemical structures produced from the breakdown of fatty acids in the liver when the body cannot use glucose (or sugar) for energy. Instead of getting energy from carbohydrates or glucose, the body relies on energy from fat.

The production of ketones can occur during fasting, when following a low-carbohydrate diet (keto diet), or in people with diabetes when blood sugars are high and there is not enough insulin to utilize glucose.

People with diabetes who have elevated ketones can develop a dangerous condition called diabetic ketoacidosis (DKA). Without treatment, this condition is life-threatening. Learn more about ketone levels, what they mean, and when to test for them.

Ketone Levels and What They Mean

If you have diabetes, you will want to understand the difference between trace, moderate, and high ketone levels and what to do in each circumstance. Ketones typically develop when blood glucose levels are high.

People with diabetes can develop trace, moderate, and high ketone levels for a variety of reasons. Some reasons for ketone development include:

• Accidentally or purposefully missing insulin doses
• Inability to eat
• Issues with insulin: For example, it has gone bad due to extreme temperatures
• Insulin pump malfunctions: A kinked or dislodged cannula, interruption of insulin due to a low insulin reservoir, a battery that has died, a leak
• Infection or illness: Can increase glucose levels due to counterregulatory hormones (cortisol and adrenaline), which requires more insulin to maintain normal blood sugar
• Surgery: Post-operative hyperglycemia requires more insulin due to the stress response.
• Delayed diagnosis of diabetes: Usually type 1 diabetes

Your medical team should provide you with a plan on what to do in the event that you have ketones.

Trace or Small

If you are using a urine ketone test, you'll use the color-coded strip to determine the amount of ketones. A ketone meter that measures blood ketones should read less than 0.5 to 0.6 millimoles per liter (mmol/L).

Trace or small amounts of ketones are typically treated with a correction dose of insulin every two to three hours and drinking lots of sugar-free fluids until your blood sugar returns to normal. Fluids help to flush out the extra glucose into the urine.

However, if you give a correction dose of insulin and your blood sugars are still not improving, you should contact your physician.

Moderate and Large

Moderate to large levels of ketones will warrant a call to your medical team. Depending on how you are feeling and what level your blood sugars are, they may need to calculate a "ketone dose" of insulin. They will also advise you on how to stay hydrated and how to continue to test your blood sugar and ketones.

When to Test for Ketones

Clinical recommendations are to test for ketones when blood sugars are elevated or when someone with diabetes is ill. These are provided so that early intervention can reduce the risk of DKA.

Ask your healthcare professional when and how you should test for ketones. You should have a sick day management care plan. In addition, you should have a plan for when to check ketones when your blood sugars are high. If you are ever in doubt and uncertain what to do, it's always better to check.

Many experts advise checking for ketones when your blood glucose is more than 240 milligrams per deciliter (mg/dL), while others suggest checking when your blood glucose is more than 300 mg/dL. The scenario should be individualized based on a person's age, specific situation, and medication regimen.

For those who use insulin pump therapy, it is advised to test for ketones when blood sugars are greater than 300 mg/dL for no reason at all or if your blood sugar has not come down in two hours after a correction dose of insulin.

If you are pregnant and have type 1 diabetes, the Association of Diabetes Care and Education Specialists advises checking for ketones when blood sugars are greater than 200 mg/dL.

The American Diabetes Association recommends that you check for ketones every four to six hours when you are ill (if you have a cold or the flu, for example), and to check every four to six hours when your blood sugar is more than 240 mg/dL.

People with diabetes who take oral medications of the class of sodium-glucose co-transporter 2 (SGLT-2) inhibitors can develop DKA even with normal glucose levels. These medications include Forxiga (dapagliflozin), Invokana (canagliflozin), Jardiance (empagliflozin), and Steglatro (ertugliflozin).

If you take an SGLT-2 inhibitor and are ill, it is advised to test for ketones, despite normal blood sugar levels. If ketones are present, you'll need to call your medical team, as they may advise you to stop your medication.

Also, check for ketones when you have any symptoms of DKA. Symptoms of DKA include:

• Excessive thirst
• Frequent urination
• Nausea and vomiting
• Lethargy
• Deep breathing
• Fruity breath
• Stomach pain
• Coma (if not treated)

How to Test Ketones

Ketones can be tested at home via urine using a urine ketone strip or a blood ketone meter. To use a urine ketone strip, the strip is dipped into your urine sample and the color change is compared to a provided color array.

To use a blood ketone meter, you stick your finger with a lancet to draw blood and apply a drop to the strip inserted into the meter. The meter provides a result.

Experts suggest using a blood ketone meter because it can detect ketones before they show up in the urine. In addition, results from urine can be skewed due to other circumstances such as dehydration.

However, clinicians acknowledge that blood ketone test strips and meters are more expensive than urine strips. Call your healthcare provider to see if your insurance covers a blood ketone meter and test strips. If they do not, ask your physician if urine ketone strips are sufficient.

What to Do If Your Ketone Levels Are Off

If you have diabetes or are the caretaker of someone who does, you should always have a care plan for managing ketones. If you do not have one, make sure you call your diabetes team to create one.

Keep backup supplies, such as extra insulin. Additionally, all people with diabetes should have a medic alert—whether it be a bracelet or a necklace. In the event of an emergency, you want people to be able to identify that you have diabetes.

Exercise is never recommended when you have ketones. Exercising when you have ketones can cause your blood sugar levels and ketones to go even higher.

Make sure you have a way to reach your medical team at any time of day or night. Call them if you have moderate to high levels of ketones, especially if your blood sugar is high and if you are feeling ill. They will give you instructions on what to do in your specific situation.

Summary

Ketones develop when the body cannot use sugar for fuel and starts to utilize fat instead. In people with diabetes, excessive ketone production can result in a dangerous condition called diabetic ketoacidosis. This is more common in people with type 1 diabetes but can occur in anyone with diabetes.

If you have diabetes, you should test for ketones when your blood sugar is high or you are ill. You can test for ketones at home with a urine dipstick or with a blood ketone meter. Make sure you receive proper education on ketone management and create a care plan with your medical team.

A Word From Verywell

Detecting and treating ketones early can prevent an emergency. Understanding when, how, and what to do with your ketone information is important. Make sure you have supplies to check for ketones, plenty of sugar-free beverages, and access to your ketone management plan.

In the event that you have moderate to large levels of ketones, or your blood sugar is elevated, and you are not feeling well, call your medical team.