Managing Diabetes

Testing for Ketones

What are ketones?

Ketones are chemicals produced in the liver as a result of breakdown of fat.

The presence of insulin usually keeps this process at bay. A lack of insulin may result in unrestricted breakdown of fat leading to an excess of ketones which in turn causes the condition ‘ketoacidosis’. The ketones build up in the bloodstream and spill over into the urine causing ‘ketonuria’ which can be detected by simple tests.

Why does the body start producing ketones?

The body burns fat when it can’t use glucose for energy. Without insulin we are unable to utilise glucose which then accumulates in the blood.

Who is at risk for ketone production?

Anyone can produce ketones for various reasons. People who have type 1 diabetes are particularly at risk

When should I test for ketones?

You should test for ketones if you are unwell with any of the following conditions.

  • fever
  • vomiting or diarrhoea
  • abdominal pain
  • ·greatly increased thirst or volume of urine
  • very high blood sugars
  • Pregnancy
  • Any physical or emotional stress
  • If your breath smells sweet or fruity

What are the ways of testing for ketones?

There are three methods of testing available in the UK.

1. KetostixR (Bayer Diagnostics)

Ketostix reagent strips - image of package

Reagent strips available in a 50 strip pack.

2. AcetestR (Bayer Diagnostics)

Reagent tablets available in a 100 tab pack.

3. Ketur TestR (Roche Diagnostics)

Reagent strips – 50 strip pack.

Is it better to test for blood ketones?

There are devices which test for blood ketones and measure ketone concentrations in the blood. This is not strictly necessary as the test for urinary ketones is very sensitive and is capable of detecting tiny amounts of ketones in the urine. Measurement of ketone levels in the blood is expensive and does not give any adittional benefit.

How do I test for ketones?

Dip a test strip or tablet in a sample of urine. A test strip may simply be held in the urine stream. If the colour changes you have ketones in your urine.

What to do in case of a positive test

If the test result shows a trace of ketones or small amount of ketones

  • Drink plenty of water
  • Avoid exercise
  • Test your blood glucose and urine for ketones every 4 hours,particularly if blood sugars higher than 15 mmol/l
  • If no improvement, discuss with your nurse or on-call doctor
  • If the result shows a large amount of ketones
  • Inform your doctor
  • Drink a glass of water every 30-60 minutes
  • If your blood sugars are high and you have short-acting insulin, consider taking an additional dose of insulin

If you continue to vomit and your urinary ketones are strongly positive contact your doctor or seek hospital admission as a matter of urgency.


Dr Nishan Wijenaike
Consultant Physician
West Suffolk Diabetes Service
February 2004