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Blood ketone monitoring

Learning about how to monitor ketones is an important part of type 1 diabetes management. Here we’ll explain what to look out for, how to measure for ketones, what the results mean and if you need to do anything.
Content last reviewed and updated: 15.08.2023


A person using a blood glucose meter to measure for blood ketones

What are ketones?

Ketones are produced when the body doesn’t have enough insulin to use glucose as a source of energy, so it starts breaking down fat as another way to make energy.

Small amounts of ketone are generally harmless to the body, but too many ketones are dangerous and can cause the body to become too acidic, which can be life-threatening.

Why are ketones bad?

If ketone levels build up they can cause the body to become more acidic. This can make you feel very unwell and can lead to diabetic ketoacidosis (DKA). DKA is a serious condition which needs immediate medical attention. Read more about DKA and how to identify, treat and prevent it.

What might cause ketones to rise?

Ketones build up when the body doesn’t have enough insulin to convert glucose to energy. This doesn’t happen most of the time, because people with type 1 learn how to balance their blood glucose levels with how much insulin they’re taking.

However, there are times when you may need more insulin than you usually do. For example, if you’re ill, your body releases stress hormones which can trigger a release of blood glucose stored in your liver. This means you will need more insulin than usual. Stress, not surprisingly, also releases stress hormones which can have the same effect.

Not taking insulin, or enough of it, can lead to a build up of ketones. Lots of people go through periods where they find type 1 difficult, so if you feel like this, you’re not alone. Speak to your Diabetes Healthcare Team, friends, family, online communities, or contact us at

What is a blood ketone meter?

A blood ketone meter measures the ketones in your blood, in the same way that a blood glucose meter measures glucose. In fact, blood ketone meters and blood glucose meters look very similar and are often combined into one device. They are just measuring different things.

Where can you get a ketone meter?

You can get a ketone meter through your Diabetes Healthcare Team clinic or GP. If you’re refused one from your GP because of the cost, ask your hospital-based Diabetes Healthcare Team to write to your GP to request a prescription.

What blood ketone meters are available?

Meters available in the UK, with ketone test strips on prescription, include GlucoMen Areo 2kFreeStyle Optium Neo and CareSens Dual.

When should you test your blood ketone levels?

You should test your ketone levels if your blood glucose levels are above 11mmol/L.

If you have any symptoms of DKA you will need to test your ketone levels – or have them tested – as quickly as possible. If you don’t have access to a ketone monitor immediately, go to the hospital straight away.

You should also check your ketones regularly if you are ill. Find out more about how to manage type 1 when you’re unwell.

What is the normal range for blood ketone levels?

Lower than 0.6 is a normal reading for blood ketones.

What to do if you have high blood ketone levels?

0.6 to 1.5mmol/L means you’re at a slightly increased risk of DKA and you should test again in two hours.

1.6 to 2.9mmol/L means you’re at an increased risk of DKA and should contact your Diabetes Healthcare Team or GP as soon as possible.

3mmol/L or above means you may be in DKA and should get medical help immediately.

Blood v. urine ketone tests

There are kits available that test the level of ketone through urine instead of blood. However, this is not as accurate at blood ketone testing. This is because ketones get to the blood before they get to the urine, so a blood ketone test will show you what’s happening more quickly than one that tests your urine. This is important because high ketone levels need to be treated quickly.

More helpful information

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A blood glucose meter which is also known as a blood glucose monitor

What is DKA?

Learn more about diabetic ketoacidosis (DKA) and how to prevent it

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Read more about how flash glucose monitoring can help you manage your glucose levels

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