Managing blood glucose levels - Bedfordshire Hospitals NHS Trust (2025)

Rules for when you are sick

Check your blood glucose every two hours.
Check your blood ketones every two hours.
Follow the SICK DAY RULES in the next section.

When you are ill with a cough, cold or tummy bug, your body needs more energy to fight the illness; and you might not eat as much as usual. These things together can make you very ill.

When you are ill, it is very important that you:

Check your blood glucose every two hours
Check your blood ketones every two hours
Follow the SICK DAY RULES to work out if you need extra insulin and/or hypo treatments

What are Ketones and what is DKA?

When your body can’t get enough energy from your blood glucose, it starts to breakdown your body fat into glucose to try and get more energy.

When fat breaks down into glucose, it also produces acids called ketones. If ketones build up in your blood they can make you very poorly. This is called DKA, which is short for Diabetic Keto-acidosis.

Without insulin, glucose is unable to be processed by the body.
The liver produces more glucose to feed the body, but without insulin, the glucose accumulates in the bloodstream.
The body needs to find an alternative source of energy and starts breaking down fat. The breakdown of fat produces ketones, which then build up in the bloodstream.
Ketones and glucose are transferred into the urine. The kidneys use water to clear the blood of excess glucose and ketones.
While the body attempts to get rid of the ketones and glucose, a lot of water is lost. This can lead to dehydration and may worsen the ketoacidosis.

What causes DKA?

Being ill
Not taking enough insulin

What are the clues that I moving towards DKA?

Thirst
Weeing a lot
Tummy pain
Drowsiness, rapid breathing
High blood sugars
Nausea / vomiting

How do I avoid getting DKA?

DKA can happen when:

you haven’t taken enough insulin – because your body can’t move the glucose into the muscles where it is needed.
you are ill – because your body might use up all your blood glucose to fight off infection

To avoid DKA:

Always take your insulin at the right time and in the right quantities.
When you are ill, test your blood glucose and ketones every two hours.
If you have ketones in your blood: Follow the SICK DAY RULES: these tell you how to get rid of the ketones that are building up in your blood.
If you are ill; if your blood glucose is consistently high OR if you know you haven’t taken enough insulin: Follow the SICK DAY RULES to stop ketones building up
The simple sick day rules below show what to do when you are Ill or have ketones over 0.6.

SICK acronym:

Sugar

Check your blood glucose every two hours.

Insulin

Always take your insulin – not taking it could lead to DKA.

Carbs

Sip lots of fluid.

If your blood glucose is high, drink sugar-free liquids.

If your blood glucose is low, drink carb-containing liquids.

Ketones

Check your ketones every four house. If your ketones are above 0.6 call for advice.

How do I test for ketones?

To test your blood ketone levels with the finger prick method you will need:

Blood glucose meter
Blood ketone test strips
Finger pricker device (lancing device)
Lancets

How to test your blood ketones with the finger prick method:

Wash your hands in soap and warm water
Dry your hands thoroughly
Put a fresh blood ketone test strip into the blood glucose meter
Put a lancet into the lancing device
Prick your finger (remember Not to squeeze the finger)
Put the blood onto the test strip
Record the result in your app or write it down
Throw away the used lancet in the sharps bin
Throw away the used test strip

Results

Normal ketones

Less than 0.6

Moderate ketones

0.6 – 1.5

High ketones

1.5 or higher

What to do if: your BG is less than 14 with Ketones over 0.6

ALWAYS TAKE YOUR INSULIN – EVEN IF YOU’RE UNWELL AND DON’T FEEL LIKE EATING, YOU WILL STILL NEED INSULIN

BG less than 4

Treat for a Hypo as shown on page 21 and retest BG after 15 minutes
If your child is struggling to keep food down or can’t eat / drink –
give dextrose gel and call for advice
If your child is drowsy or has reduced consciousness give IM Glucagon and call 999

BG 4 – 7

Drink sugary drinks. Sip 150ml every two hours
You may need to decrease your bolus insulin
Call for advice

BG 8 – 14

Keep sipping sugar free drinks
Take the usual meal insulin bolus and correction dose at meal times

Re-check your BG and ketones every two hours

If your child is vomiting, unable to eat or has ketones over 1.5. Call for advice.

What to do if: your BG is over 14 (insulin pen user)

ALWAYS TAKE YOUR INSULIN – EVEN IF YOU’RE UNWELL AND DON’T FEEL LIKE EATING, YOU WILL STILL NEED INSULIN

Normal ketones (Less than 0.6)

Take your usual correction dose of insulin with your usual meal insulin bolus
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If blood glucose level is going down, it is a good sign but monitor closely throughout the dayIf BG is increasing but ketones are less than 0.6mmol/L give another correction dose
If ketones 0.6-1.5mmol/L follow ‘Moderate Ketones‘ advice
If ketones >1.5mmol/L follow ‘High Ketones‘ advice
See Also
What is dangerously high blood sugar for type 2 diabetes?

Moderate ketones (0.6 – 1.5)

Take 5% of your total daily dose (TDD) as additional NovorapidOR
Take your usual correction dose of Novorapid, if that is higher
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If ketones are less than 0.6 follow ‘Normal Ketones‘ adviceIf BG is increasing but ketones still 0.6 – 1.5mmol/L:
Take another 5% of TDD or usual correction dose as additional novorapid
Re-check BG and ketones every 2 hours even through the night.
If ketones increase to 1.5mmol/l or more, follow the ‘High Ketones‘ advice
If ketones are not dropping despite 2 correction call for advice

High ketones (1.5 or higher)

Take 10% of your total daily dose (TDD)OR
0.1 unit/kg body weight as additional Novorapid
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If ketones are less than 0.6 follow ‘Normal Ketones‘ adviceIf BG is increasing but ketones have reduced to
0.6 – 1.5mmol/L, follow ‘Moderate Ketones‘ advice
If ketones are still >1.5mmol/L: take another 10% of TDD or 0.1units/kg as additional novorapid
If ketones are not dropping despite 2, corrections call for advice
If vomiting with high ketones, they may have DKA, Call for advice.

If your child has BG over 14 with ketones and is vomiting, this could be DKA. Call for advice

What to do if: your BG is over 14 (insulin pump user)

ALWAYS TAKE YOUR INSULIN – EVEN IF YOU’RE UNWELL AND DON’T FEEL LIKE EATING, YOU WILL STILL NEED INSULIN

Normal ketones (Less than 0.6)

Take your usual correction dose of insulin with your usual meal insulin bolus
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If blood glucose level is going down, it is a good sign but monitor closely throughout the dayIf BG is increasing but ketones are less than 0.6mmol/L give another correction dose
If ketones 0.6-1.5follow ‘Moderate Ketones‘ advice
If ketones 1.5 or higher follow ‘High Ketones‘ advice

Moderate ketones (0.6 – 1.5)

Take 5% of your total daily dose (TDD) as additional NovorapidOR
Take your usual correction dose of Novorapid, if that is higher
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If ketones are less than 0.6 follow ‘Normal Ketones‘ adviceIf BG is increasing but ketones still 0.6 – 1.5:
Continue to give 5% of TDD or usual correction dose as additional novorapid
Re-check BG and ketones every 2 hours even through the night.
If ketones are 1.5 or higher, follow the ‘High Ketones‘ advice
If ketones are not dropping despite 2 correction call for advice

High ketones (1.5 or higher)

Give 10% of your total daily dose (TDD)OR
0.1 unit/kg body weight as additional Novorapid
Drink plenty of water/sugar free drinks to stay hydratedRe-check your BG and ketones in two hours
If ketones are less than 0.6 follow ‘Normal Ketones‘ adviceIf BG is increasing but ketones are 0.6 – 1.5mmol/L, follow ‘Moderate Ketones‘ advice
If ketones are 1.5 or higher:
Give another 10% TDD or 0.1units/kg as additional novorapid
If ketones are not dropping despite 2 corrections call for advice
If vomiting with high ketones, they may have DKA, call for advice

If your child has BG over 14 with ketones and is vomiting, this could be DKA. Call for advice