Ketone Levels: Where and How Should I Check?

Ketones are chemical structures produced by 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 gets energy from fat.

The production of ketone bodies can occur during fasting, following a low-carb diet (keto diet), or when people with diabetes have high blood sugar and don’t have enough insulin to use glucose.

People with diabetes who have elevated ketone bodies may develop a dangerous condition called diabetic ketoacidosis (DKA). This condition can be life-threatening if left untreated. Learn more about ketone levels, what they mean, and when to get tested.

Ketone Levels and What They Mean

If you have diabetes, you will need to understand the difference between micro, moderate and high ketone levels and what to do in each case. Ketone bodies are usually formed when blood sugar levels are high.

Trace, moderate, and high ketone levels can occur in people with diabetes for a number of reasons. Some reasons for the formation of ketone bodies include:

  • Accidental or intentional missing insulin dose
  • inability to eat
  • Insulin problems: for example, spoilage due to extreme temperatures
  • Insulin pump failure: kinked or dislodged cannula, insulin interruption due to insufficient insulin reservoir, dead battery, leaking
  • Infection or disease: As counter-regulatory hormones (cortisol and epinephrine) increase blood sugar levels, this 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 healthcare team should give you a plan to tell you what to do if you are in ketosis.

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If you are using a urine ketone test, you will use a color-coded bar to determine the amount of ketones. The ketone meter reading for blood ketones should be less than 0.5 to 0.6 millimoles per liter (mmol/L).

Treat traces or small amounts of ketones with a corrected dose of insulin, usually every two to three hours, and drink plenty of sugar-free fluids until your blood sugar returns to normal. Fluids help expel excess glucose into the urine.

However, if you are given a corrected dose of insulin and your blood sugar still does not improve, you should contact your doctor.

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Moderate to high levels of ketones will require a call to your healthcare team. Depending on how you’re feeling and your blood sugar levels, they may need to calculate a “ketone dose” for insulin. They will also give you advice on how to stay hydrated and how to keep testing your blood sugar and ketones.

When to Test for Ketones

The clinical recommendation is to test for ketone bodies when blood sugar is elevated or when someone with diabetes is sick. These are provided so that early intervention can reduce the risk of DKA.

Ask your healthcare professional when and how to test for ketones. You should have a sick leave management care plan. Also, you should plan when to check for ketones when your blood sugar is high. If you’re in doubt and not sure what to do, it’s best to check it out.

Many experts recommend checking ketone bodies when your blood sugar exceeds 240 milligrams per deciliter (mg/dL), while others recommend checking when your blood sugar exceeds 300 mg/dL. The regimen should be individualized based on the individual’s age, specific circumstances, and medication regimen.

For those on insulin pump therapy, it is recommended to test for ketone bodies when blood glucose is unprovoked greater than 300 mg/dL or when blood glucose does not drop within two hours of a corrected dose of insulin.

If you are pregnant and have type 1 diabetes, the Association of Diabetes Care and Education Specialists recommends that you check for ketones when your blood sugar is above 200 mg/dL.

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

DKA can occur in diabetic patients taking oral medications that are sodium-glucose cotransporter 2 (SGLT-2) inhibitors, even when blood glucose levels are normal. These include Forxiga (dapagliflozin), Invokana (canagliflozin), Jardiance (empagliflozin), and Steglatro (ertugliflozin).

If you are taking an SGLT-2 inhibitor and are sick, it is recommended that you test for ketones, even though blood sugar levels are normal. If ketone bodies are present, you will need to call your healthcare team as they may advise you to stop taking your medication.

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

  • excessive thirst
  • frequent urination
  • nausea and vomiting
  • lethargy
  • take a deep breath
  • fruity
  • stomachache
  • coma (if not treated)

How to Test for Ketones

Ketones can be tested for ketones at home using urine ketone strips or a blood ketone meter. To use a urine ketone test strip, dip the test strip into your urine sample and compare the color change to the color array provided.

To use a blood ketone meter, you insert your finger with a lancet to draw blood, then place a drop on the strip inserted into the meter. The meter provides the results.

Experts recommend a blood ketone meter because it can detect ketone bodies before they appear in the urine. Also, the results of urine may be skewed due to other conditions such as dehydration.

However, clinicians admit that blood ketone test strips and blood glucose meters are more expensive than urine test strips. Call your healthcare provider to find out if your insurance covers blood ketone meters and test strips. If not, ask your doctor if urine ketone test strips are sufficient.

What to do if your ketone levels drop

If you have diabetes or are the caregiver of someone with diabetes, you should always have a care plan for managing ketone bodies. If you don’t have one, be sure to call your diabetes team to create one.

Keep spare supplies, such as extra insulin. Also, all people with diabetes should have a doctor’s alert — whether it’s a bracelet or necklace. In an emergency, you want people to recognize 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 rise.

Make sure you have a way to contact your healthcare team at any time of the day or night. Call them if you have moderate to high ketone levels, especially if your blood sugar is high and you are not feeling well. They will give you instructions on what to do in your specific situation.

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Ketones form when the body can’t use sugar for fuel and starts using fat. In people with diabetes, excess ketone body production can lead to a dangerous condition called diabetic ketoacidosis. This is more common in people with type 1 diabetes, but can happen to anyone with diabetes.

If you have diabetes, you should test for ketones when your blood sugar is high or you are sick. You can test for ketones at home using urine dipsticks or a blood ketone meter. Make sure you are properly educated about ketone management and work with your healthcare team to develop a care plan.

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Early detection and treatment of ketones can prevent emergencies. It is important to know when, how and what to do with your ketone body information. Make sure you have supplies to check for ketones, plenty of diet drinks, and access to your ketone management plan.

Call your healthcare team if you have moderate to high amounts of ketones, or if your blood sugar is elevated and you are not feeling well.

Frequently Asked Questions

  • What is ketosis?

    Ketosis occurs when the body converts to fat in the form of ketones as its main source of energy. The liver produces ketones when there is too little glucose in the body to use as fuel.

  • What is Ketoacidosis?

    Ketoacidosis is a dangerous acute condition that occurs when too much ketones build up in the body, causing the blood to become acidic. Diabetic ketoacidosis (DKA) is more common in people with type 1 diabetes, but can also occur in people with type 2 diabetes.

  • What happens if someone with high ketone levels goes untreated?

    If people with diabetes have high levels of ketone bodies and go untreated, they can develop ketoacidosis, which can be fatal. Treatment of DKA is performed in the hospital and requires correction of hyperglycemia and acidosis, volume replacement, and prevention of hypokalemia (potassium).