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Ketogenic dietary therapy (KDT) monitoring

Patient information A-Z

What is ketogenic dietary therapy (KDT)?

KDT is used as a treatment for drug resistant epilepsy and some metabolic conditions. By significantly reducing the amount of carbohydrate within a diet and increasing the fat, the body will produce ketones. These ketones are used as an alternative energy source in the absence of glucose and have been proven to reduce seizures for some children.

Ketones are not usually present when a person is well; therefore it is important to monitor ketone levels to ensure they do not exceed the therapeutic range.

This leaflet includes:

  • routine monitoring
  • urine ketone testing
  • blood ketone testing
  • emergency testing
  • hyperketosis
  • hypoglycaemia
  • expectations for nurseries and schools

Routine monitoring

As we do not normally have ketones present in our bodies it is important that the ketone levels are monitored regularly. This will ensure they are in the target range and do not rise above this range. This can be done routinely by checking the urine or checking the blood. Each method measures a different type of ketone, therefore you may notice differences between the blood and urine results. It is up to you and your family whether you choose to routinely check the blood or urine ketone levels.

We encourage you to check ketone levels twice daily.

Urine monitoring

One of the ketone bodies, acetoacetate, can be measured in the urine using Ketostix. These will be prescribed by your GP.



  1. Urinate directly onto the end of the stick or dab in a fresh nappy (you may need to place a piece of cotton wool in the pad).
  2. Wait 15 seconds.
  3. Record your result.
  4. If you obtain the darkest colour (++++ / 16mmol/L) on two consecutive occasions, check the blood ketone level. This is to ensure that the ketones in the blood are within the target range.

Blood monitoring

The main ketone produced is beta-hydroxybutyrate which can be measured in the blood using a home blood testing kit. You will be provided with a blood testing monitor when you have your initial KDT training session.

Home blood testing kit


  1. Wash your child’s hands in warm water
  2. Ensure there is a new lancet (needle) in the lancing device.
  3. Unwrap the ketone testing strip and have the blood testing meter ready (do not insert the testing strip at this stage).
  4. Prick the side of your child’s fingertip with the lancing device and gently squeeze the finger to assist blood flow.
  5. Place the striped end of the ketone strip into the meter and the meter should turn on automatically.
  6. Once a picture of a drop of blood appears on the display screen, touch the end of the ketone testing strip gently onto the blood spot and allow the blood to be taken up by the testing strip.
Finger prick using lancing device
Home blood testing meter screen displaying 'Er3' and the time
If the screen displays Er 3 or E-3, the amount of blood was insufficient and a new sample will need to be obtained

7. Record the result. If the reading is higher than 6.0 follow your care plan by giving the emergency carbohydrate dose (see below).
8. Discard the used lancet safely in your yellow sharps bin.

In an emergency

Hyperketosis (high ketone levels) and hypoglycaemia (low blood glucose levels) are a risk when on KDT and require intervention. For most children, the treatment for both hyperketosis and hypoglycaemia will be 5g of carbohydrate.

Emergency carbohydrate (5g)

  • 50ml pure fruit juice (not a low sugar variety)
  • 1 yellow scoop Maxijul (5g) in 30ml of water
  • 8ml Polycal


Every child has a different threshold to high ketones. Signs of hyperketosis are:

  • becoming very red in the face
  • panting
  • vomiting or feeling sick

If your child shows any of these signs check the blood ketone level using your meter. If the level is over 5mmol/L treat with the emergency carbohydrate (above). The next meal or feed should be given at the normal time.

If a child is symptom free but the blood ketones are above 6 mmol/L, treat with 5g carbohydrate. If the meter is not available, treat the symptoms with the emergency carbohydrate.


Sometimes blood sugars can fall, especially when starting the diet. Signs of hypoglycaemia are:

  • pallor, becoming pale
  • tremor, shaking
  • faintness, lack of energy
  • sweating

If your child shows any of the above signs, check their blood glucose level. This can be measured using the same meter used for checking ketone levels, but using the blood glucose strips (these may be blue or may come in a separate pot).

If blood glucose levels are less than 2.6mmol/L, treat with 5g of carbohydrate.

Check blood glucose again at 15 minutes after treatment.

  • If the symptoms have subsided, give your child their next meal straight away.
  • If the symptoms have not subsided, give another dose of carbohydrate.

Expectation for schools and nurseries

Schools and nurseries are not expected to check children’s blood ketone levels or blood glucose levels. If they are concerned a child is displaying signs of hyperketosis or hypoglycaemia, they are advised to give the child 5g of emergency carbohydrate (see above).

On starting KDT, parents are provided with a letter for nursery/ school which describes the symptoms of hyperketosis and hypoglycaemia. We advise schools and nurseries to treat children with the emergency carbohydrate if they are concerned.

Our contact information

Dietitians 01223 216 655: queries about the diet, ketones, low blood sugars or high ketones, change of feed regime, or home delivery company.

Neurology nurses 01223 216 662: queries about increases in seizures, change in medications and other concerns.

In an emergency, contact the paediatric neurology on-call registrar.

During working hours, call the Child Development Centre 01223 586618.

Out of hours or at the weekend, call Addenbrooke’s Hospital on 01223 245151 and ask for the on-call paediatric neurology registrar.

Non-urgent advice: Notes

Add notes here.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

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Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151