Ketone Testing within Hospital

Objectives

We seek to provide more information on when blood ketones should be checked for people with diabetes in the hospital setting, what these levels mean and which actions are required to be taken.

Scope

When to check blood ketones and what to do with the results.

Audience

All healthcare professionals who are involved in looking after people with diabetes in hospital settings in NHS Borders.

Raised ketones

Call your senior or the diabetes on call team if you aren't sure what to do, or if there is a clinical concern.

Type 1 diabetes or pancreatic diabetes

• Ketones can develop if insulin deficient due to insulin omission or increased requirements due to intercurrent illness
• If ketones accumulate, there is a risk of developing diabetic ketoacidosis (DKA)
• Capillary ketones should be checked if capillary blood glucose (CBG) is >14mmol/L.

Type 2 diabetes

• Much less likely to develop DKA unless they have a severe intercurrent illness or are on an SGLT2 inhibitors (SGLT2i) ("-gliflozins")
• There is a small risk of euglycaemic DKA with SGLT2i
• SGLT2i should be stopped if patients are fasting, have a reduced oral intake or are unwell with an acute illness.

Other reasons for raised ketones

• Other reasons for raised ketones include starvation, alcohol, sepsis and a ketogenic diet.
• Always consider DKA but raised ketones can simply be a sign of acute illness and highlights the need for an urgent medical review.

Management of ketones in type 1 or pancreatic diabetes

Ketones < 0.6

• Considered normal
• No extra intervention needed

Ketones 0.6 – 1.4

• Slightly raised
• Encourage to drink sugar free fluids
• Consider a correction dose of short acting insulin to correct hyperglycaemia
• Repeat CBG and ketones in 2hrs
• If rising, contact diabetes on call in hours or senior out of hours

Ketones 1.5 – 2.9

• Raised
• Encourage to drink sugar free fluids
• Give an extra correction dose of short acting insulin at 10% of their total daily dose (TDD*) of insulin to correct hyperglycaemia
• Repeat CBG and ketones in 2hrs
• If rising, contact diabetes on call in hours or senior out of hours

Ketones > 3

• Very raised
• Check venous blood gas - if acidotic, treat as DKA
• If not acidotic
  • Encourage to drink sugar free fluids
  • Give an extra correction dose of short acting insulin at 20% of their TDD* of insulin to correct hyperglycaemia
  • Repeat CBG and ketones in 2hrs
  • If rising, contact diabetes on call in hours or senior out of hours

• *Total daily dose (TDD) of insulin can be calculated by adding up all the long and short acting insulin a person takes in a 24hr period
• Avoid correction doses closer than 2 hours apart as there is a risk of insulin stacking and hypoglycaemia

Call your senior or the diabetes on call team if you aren't sure what to do, or if there is a clinical concern

Ketone Testing within Hospital

*To calculate TDD of insulin-add up all insulin doses usually administered in a 24 hour period
 For more information please see: Raised ketones | NHS Lothian Right Decisions

When should ketones be checked?

• In people with type 1/pancreatic diabetes with acute illness or hyperglycaemia > 14mmol/L
• In any patient with diabetes with severe nausea/vomiting or acidosis
• In any patient on SGLT2i who is acutely unwell
• In patients with type 2 diabetes in the context of hyperglycaemia and acute illness, in secondary pancreatic failure and/or in pancreatitis.

Ketones can be falsely lowered in patients who have raised haematocrit such as those who are acutely dehydrated or unwell.

What is Diabetic Ketoacidosis (DKA)?

DKA is a life-threatening metabolic disturbance most commonly in those with type 1 diabetes resulting in hyperglycaemia, dehydration, electrolyte imbalance, ketone production and acidosis. DKA can occur with or without hyperglycaemia. 

The presence of ketones in blood signifies a risk of diabetic ketoacidosis (DKA).

Patients with normal blood sugars and raised ketones on SGLT2i will usually need treated on the DKA protocol and require senior review.

Quality Control

QC should be carried out prior to a ketone test on a patient or in the case of repeated use once within 24 hours.