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Who is this for?

This guide is for children and young people with Type 1 diabetes, and their families, to help manage high blood glucose levels and illness when using multiple daily insulin injections.

✅Understanding Blood Glucose Targets

  • Your ideal blood glucose level should be between 3.6 and 9 mmol/L. 
  • This target applies whether you're using a finger prick test or a continuous glucose monitor (CGM). 
  • Aim to stay in this range at least 70% of the time, and try to spend less than 4% of the time below 3.6 mmol/L.

📈When Glucose Is High

  • If it’s been more than 2 hours since your last dose of rapid-acting insulin and your levels are still high, you might need an extra injection of insulin.
  • Only use rapid-acting insulin (e.g., NovoRapid, Humalog, Apidra, Fiasp or Lyumjev) for correction boluses.

High Glucose + Ketones = Act Fast

  • If you have high blood glucose and ketones, it means your body doesn’t have enough insulin. 
  • You’ll need to increase your insulin dose more than usual. 

Using a Bolus Calculator

  • We assume you’re using a bolus calculator like the mylife™ app (free on Apple and Google Play). 
  • If not, use your Insulin Sensitivity Factor (ISF) to calculate your correction dose. Ask the diabetes team if you do not know what this is. 

💧 Stay Hydrated

  • High blood glucose and ketones can make dehydration worse. 
  • Drink sugar-free fluids – especially when your blood sugar is above the target range.

What To Do: Step-by-Step

Step 1: Check for High Glucose

High glucose = over 9.0 mmol/L (via finger prick or CGM) and more than 2 hours since the last injection of rapid acting insulin. 

Check blood ketones if glucose above 14mmol/L.

Step 2: Give a correction dose of insulin using instructions below:

Ketone Level (mmol/L) What to do
Below 0.6 (normal) Use your bolus calculator. Give the recommended correction dose using rapid acting insulin. Check again in 2 hours.

0.6 to 1.5

 Use your bolus calculator, then increase dose by 50%. Give the correction dose using rapid-acting insulin. Drink sugar-free fluids. Recheck in 2 hours.

Over 1.5

 Use bolus calculator and double the dose (increase by 100%). Give the correction dose using rapid acting insulin. Drink sugar-free fluids. Recheck in 2 hours.
Over 1.5 and struggling Go to A&E or call 999 if: vomiting, drowsy, unable to drink, has belly pain, or breathing heavily. This could be ketoacidosis.

Step 3: Keep Checking

  • Recheck glucose and ketones every 2 hours. 
  • Go back to Step 2 as needed. 
  • Always leave 2 hours between rapid-acting insulin doses. 
  • Contact the diabetes team if no improvement 

Contact the Diabetes Team

​​​​​​​🔗 More Info: 

Visit our Children and young people's diabetes​​​​​​​ page for fact sheets and resources.

Services

Printing of this document is only valid on the day printed, please refer to the website for most up to date information:

https://www.uclh.nhs.uk/patients-and-visitors/patient-information-pages/dealing-high-glucose-levels-abc-multiple-daily-injections

Service information

Page last updated: 30 June 2025

Review due: 01 June 2027