Ketones: what you need to know

You test for glucose,
but checking for ketones when your glucose is high is important too.

What are ketones?

Ketones are acidic chemicals that your body produces when your liver breaks down fat to use as energy because glucose is in short supply.4 This can happen to anyone, with or without diabetes, for example, if you’re missing meals or exercising hard.4

Why are ketones important in diabetes?

When you have diabetes, your body can start to produce ketones if there isn’t enough insulin available to convert glucose into energy. If something happens to reduce your supply of insulin, or to increase your body’s need for insulin, this can trigger a rapid rise in ketone production. High ketone levels can lead to a medical emergency known as diabetic ketoacidosis (DKA). If untreated, DKA can be life-threatening. People with Type 1 diabetes are more at risk of DKA, but it can also affect people who have Type 2 diabetes and use insulin.1

So it makes sense to know when you might be at risk of DKA and what to do to avoid it.

What can trigger a rise in ketone levels?

There are many factors that can increase your body’s insulin requirements or reduce the availability of insulin. Typical triggers of ketone production include2:

  • Being ill, especially with an infection, flu or fever
  • Being injured or having a hospital operation
  • Missing insulin doses or under-estimating the dose
  • Taking certain medicines, such as steroids
  • Binge drinking or using illegal drugs
  • Pregnancy
  • Having your period 

How do I know if my ketone levels are high?

High ketone levels often occur alongside high glucose levels, so your diabetes care team may advise you to test for ketones if your glucose is more than 15mmol/L, or if you feel unwell.1

If your ketone levels are raised you may also notice these symptoms2:

  • Breath that smells fruity or like nail polish remover
  • Difficulty breathing
  • Feeling sick
  • Feeling sleepy or confused
  • Increased thirst
  • Stomach pain
  • Urinating more often

How do I test for ketones?

You can test for ketones in your blood or your urine. Your diabetes care team can advise on which type of test to use.

Two meters from Abbott – the FreeStyle Libre system and the FreeStyle Optium Neo – can be used to test for ketones.

If you test your glucose and the result is higher than 13.3mmol/L you are recommended to complete a blood ketone test.3 The technique is the same as testing your blood glucose, except you use a different kind of test strip, FreeStyle Optium β Ketone Test Strips.

What do my ketone test results mean?

The table shows the range of results you might get from testing your blood for ketones. If you’re testing your urine, a result of 2+ indicates a risk of DKA, so seek medical help. 2

Blood ketone level

What you should do 

Below 0.6 mmol/L This is in the normal range
0.6 - 1.5 mmol/L Ketone levels are raised

How can I prevent high ketone levels?

The good news is you can reduce your risk of developing high ketone levels by taking care of your general health and following your care team’s advice on managing your diabetes. Useful tips2 include:

  • Test your glucose regularly
  • Follow your diabetes care plan, with regular meals and accurate doses of insulin
  • Take extra care when you’re ill by following sick day rules, testing your glucose more often and checking your blood or urine ketone level.
  • Check with your care team if you take any new medicines, as some medicines can trigger ketone production.


1. Diabetes UK 2019, Diabetic ketoacidosis (DKA), accessed 21 March 2019,

2. NHS 2017, Diabetic ketoacidosis, accessed 21 March 2019,

3. IFU FreeStyle Libre reader

4. Diabetes Education Online 2019, Ketones, University of Southern California, San Francisco, accessed 7 April 2019,



Modal libre bg * Scanning the sensor to obtain glucose values does not require lancets ×
*1. Scanning the sensor to obtain glucose values does not require lancets 2. A finger prick test using a blood glucose meter is required during times of rapidly changing glucose levels when interstitial fluid glucose levels may not accurately reflect blood glucose levels, or if hypoglycemia or impending hypoglycemia is reported but the symptoms do not match the system readings. ×

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