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Ketones

One dangerous and relatively common complication of type 1 diabetes is a condition called diabetic ketoacidosis (DKA).

When your body doesn't have enough insulin, it doesn't move glucose (sugar) into your cells, and they become starved of energy. Your body then burns fat to get energy.

Burning fat releases chemicals called ketones, which are acidic and poisonous.

Your kidneys can clear small amounts of ketones, but they can't cope with large amounts. As a result, your blood ketone level increases causing DKA, which is potentially life-threatening.

Only people with type 1 diabetes are at risk of DKA. If you have type 1 diabetes, there are two situations in which it might happen:

when you've missed insulin doses
when you're unwell and unable to eat or drink normally.

Ketosis

Ketosis is a minor increase in ketones and isn't always dangerous. It can happen if you're fasting, on a low-carbohydrate diet, or have drunk too much alcohol. If you're experiencing ketosis, you'll have slightly more than the usual level of ketones in your blood.

If you use an insulin pump, you can develop ketosis more quickly than people using injections because you have no background insulin.

Symptoms of ketosis

If you're producing ketones, you may have some of the following symptoms:

tiredness and low energy
dry mouth and thirst
nausea or vomiting
headache
sore stomach
rapid breathing or breathing difficulties
breath that smells like nail polish remover, alcohol, fermenting fruit or a fruity odour.

Testing for ketones

Many people with type 1 diabetes have a ketone testing meter. If you aren't sure if you should have a meter, ask your normal diabetes care team.

You should test for ketones if your blood glucose level is persistently higher than 14 mmol/l or if you have an infection.

Ketone testing strips

You can get blood ketone test strips and a meter on prescription from your general practice team, or you can buy them from the Diabetes Christchurch shop.

Important

Get medical help if:

your ketones are increasing despite extra insulin
your ketones are greater than 4 mmol/l and don't come down within two hours
you're feeling unwell and are worried, no matter what your ketone level is.

Interpreting ketone test results

No matter what your ketone level, if your blood glucose is below 4 mmol/l, treat yourself for low blood glucose (hypoglycaemia). Seek medical help if your blood glucose stays low or your ketones stay high.

Ketone level	What to do
more than 1.5 mmol/l	If your blood glucose is below 8 mmol/l, try to eat some extra carbohydrate, such as a sandwich, yoghurt or a banana. If your blood glucose levels are high (persistently above 14 mmol/l) you'll need extra insulin – follow the recommendations you've been given for managing sick days. Test your blood glucose and ketones every hour. You may need to have several extra doses of insulin. If your ketones are decreasing, this is reassuring. You can stop extra monitoring and ketone tests once your ketones are below 1.4 mmol/l.
1 to 1.4 mmol/l	This is slightly high. You should adjust your insulin according to the recommendations you've been given for managing sick days.
less than 1 mmol/l	Your ketone levels are reassuring, but you may need to adjust your insulin if your glucose is high according to the recommendations you've been given for managing sick days.

Ketone level

What to do

more than 1.5 mmol/l

If your blood glucose is below 8 mmol/l, try to eat some extra carbohydrate, such as a sandwich, yoghurt or a banana.
If your blood glucose levels are high (persistently above 14 mmol/l) you'll need extra insulin – follow the recommendations you've been given for managing sick days.
Test your blood glucose and ketones every hour. You may need to have several extra doses of insulin.
If your ketones are decreasing, this is reassuring. You can stop extra monitoring and ketone tests once your ketones are below 1.4 mmol/l.

1 to 1.4 mmol/l

This is slightly high. You should adjust your insulin according to the recommendations you've been given for managing sick days.

less than 1 mmol/l

Your ketone levels are reassuring, but you may need to adjust your insulin if your glucose is high according to the recommendations you've been given for managing sick days.

Written by nursing staff at the Diabetes Centre, Christchurch. Adapted by HealthInfo clinical advisers. Last reviewed November 2022.

Sources

Page reference: 300198

Review key: HIDIA-21832