Ketones: what they are and why it’s important to monitor ketone levels

High ketone levels can become toxic and dangerous for people living with type 1 diabetes. What are ketones and how and why you monitor them is outlined in this article.

Where does the body get its energy from?

Carbohydrates are the body’s main source of energy and are found in many foods and drinks. When digested, carbohydrates break down into glucose.

For glucose to be able to be used as fuel by our bodies it needs the hormone insulin to allow it to move out of the bloodstream and go into the cells. Without insulin, glucose remains in the blood stream. This means that blood glucose levels will be high and energy levels low.

If glucose is unable to get into the cells our bodies need to look for an alternative source of energy.  This source of energy is fat.

What are ketones?

When the body has to use fat for fuel, a by-product called ketones develops in the blood. In small amounts, ketones are not harmful. However, if ketone levels build up they can become toxic and very dangerous for people with type 1 diabetes. High levels can lead to a potentially life threatening condition called diabetic ketoacidosis, often referred to as DKA.  The ketones make the blood too acidic, which leads to a loss of body salts and fluids. It’s important to monitor ketone levels.

Signs and symptoms of DKA

  • Fruity smelling breath – like nail polish remover
  • Nausea
  • Vomiting
  • Stomach pains
  • Trouble breathing
  • Feel dehydrated

Importance of monitoring ketone levels

Being able to measure ketone levels is a very important part of a sick day management plan for people who have type 1 diabetes. When you become unwell or blood glucose levels are over 15mmol/L for a period of time (usually a couple of consecutive readings over 15) it is important to check your ketone level. Your ketone level helps to determine what type of action you need to take to help reduce them.

How to measure ketone levels

There are two ways you are able to measure ketones:

  1. Using a urinary ketone stick – You dip the test strip into urine collected in a small container. The stick then changes colour. The chart supplied shows how high your ketone levels are.
  2. Using a blood ketone strip – perform the test just like using a normal glucose strip. The reading will alert you to the level of ketones in your blood (see chart below). Blood ketone strips are available from your pharmacy. It is recommended that you keep some of these strips in your first aid box for use if you become sick.

Not all meters check ketones

Not all meters are able to check ketones. Some that do are:

  • Freestyle Neo which can measure blood glucose (blue strip) and blood ketones (purple strip).
  • LifeSmart 2 Plus blood glucose and ketone meter
  • CareSens Dual blood glucose and ketone monitor
  • Freestyle Libre

The table below shows ketone ranges and what those ranges may mean for you. Your individualised sick day plan will specify what action to take when your ketones reach certain levels. If you do not have a sick day plan, it is recommended that you discuss this with your diabetes health care provider.

Blood Ketone Level Urine Ketone Level What does it mean?
Less than 0.6mmol/L Negative Normal
0.6 to 1.5mmol/L Trace or small Ketones are building up.

Action is needed to reduce them.

Follow sick day plan and contact your health professional urgently if your ketones do not reduce by following the plan or you do not have a sick day plan.

1.5 to 3.0mmol/L Moderate/large Ketones are high, increasing risk of DKA developing.

Follow sick day plan and contact your health professional urgently if your ketones do not reduce by following the plan or you do not have a sick day plan.

Over 3.0mmol/L Large DKA likely – Urgent medical attention required.

(Modified from OzDAFNE Sick Day Guidelines)

If you would like more general information please call the NDSS helpline on 1800 637 700. Click here to read the NDSS factsheet on sick day management for type 1 diabetes.

Keywords: BGLsketoacidosis

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