A patient can develop diabetic ketoacidosis even when their glucose reading looks normal. Here’s why pharmacists need to keep an eye on ketones, particularly in people taking SGLT2 inhibitors.
A person with diabetes presents to the pharmacy feeling nauseous and unwell. They check their glucose. It is 8 mmol/L.
It might be tempting to rule out diabetic ketoacidosis (DKA). But that could be a dangerous assumption.
DKA occurs when the body does not have enough effective insulin and starts breaking down fat for energy, producing ketones. If ketones build up faster than the body can deal with them, the person can become seriously unwell.
While DKA is most common in people with type 1 diabetes, it can also occur in type 2 diabetes, particularly during illness or a period of reduced food intake, and in people taking sodium-glucose cotransporter 2 (SGLT2) inhibitors.
High blood glucose is a familiar feature of DKA, but it is not a requirement for diagnosis. In some cases, ketones can rise while glucose stays normal or only rises slightly – a condition known as euglycaemic DKA. It’s estimated that around 10% of DKA presentations may be euglycaemic.
Professor David O’Neal, Professor of Medicine at the University of Melbourne and St Vincent’s Hospital Melbourne, told AP that this is an important distinction for pharmacists to understand.
‘It was thought that they go hand in hand,’ he said. ‘But we realise now that’s not necessarily always the case.’
The problem with relying on glucose
Insulin has two important jobs relevant to DKA. It helps glucose move from the blood into cells, and it prevents the body from breaking down too much fat.
‘If you’ve got a relatively acute deficiency in insulin, the ketones rise quickly and can overwhelm the body’s ability to control its acid state,’ Prof O’Neal said. ‘As a result, the person gets very sick very quickly.’
Euglycaemic DKA can occur when ketones and acidosis develop without the hyperglycaemia that would normally point to DKA. This means a glucose reading on its own cannot reliably rule it out.
‘Sugars are not a good surrogate for checking for ketones,’ Prof O’Neal said.
This is particularly important for pharmacists, because patients may check their glucose regularly, assuming that a reading within their usual range means they are out of danger.
Who is at risk?
Typically patients with type 1 diabetes, who produce little or no insulin.
Missing insulin doses or an interruption to insulin delivery – such as an insulin pump problem – can cause insulin levels to fall quickly and trigger DKA.
But people with type 2 diabetes are not immune.
‘While people with type 2 diabetes are less prone to ketoacidosis, they can get it under certain circumstances or when they take certain medications,’ Prof O’Neal said.
One of the most important medication-related risks is the use of SGLT2 inhibitors.
These medicines lower blood glucose by causing the kidneys to remove more glucose through urine. While this is an important part of their therapeutic effect, it can also mean glucose does not rise as much during an episode of DKA.
When should pharmacists consider ketone testing?
Ketone testing gives pharmacists and patients information that glucose monitoring cannot.
There are several situations where pharmacists should have a lower threshold for considering ketone testing, Prof O’Neal said.
These include patients with diabetes who are:
- taking an SGLT2 inhibitor
- experiencing nausea or vomiting
- eating very little or unable to keep food down
- dehydrated
- fasting or following a very low-carbohydrate or low-calorie diet
- pregnant
- experiencing an interruption to insulin delivery
- experiencing persistently high glucose
- previously affected by DKA.
The important point is that a patient does not necessarily need to have a high glucose reading before ketone testing becomes worthwhile.
There are several ways to conduct ketone testing.
Finger prick testing – where blood ketone meters measure β-hydroxybutyrate, the main ketone present during DKA – are the recommended method for assessing ketosis in this setting. A blood β-hydroxybutyrate level ≥1.5 mmol/L is typically a warning sign of impending or mild ketosis requiring urgent clinical review, while a level of ≥3 mmol/L is a key diagnostic criterion for DKA. In this instance, pharmacists should refer patients for an urgent medical review.
Urine ketone strips are also available, but they measure a different ketone, acetoacetate. They can be less useful for tracking what is happening in real time, and are not guideline recommended.
Could ketones be monitored like glucose?
Continuous ketone monitoring could potentially transform monitoring of DKA.
Finger prick testing can provide a snapshot of ketone levels, but it is not something patients can monitor in real time.
‘You have to initiate the test yourself,’ Prof O’Neal said. ‘It’s painful, there’s blood exposure, and it’s not particularly convenient. And when you get a reading, it doesn’t tell you which way the ketones are going – if you get a reading of, say, 0.8, you don’t know whether it’s going up or down.’
Reactive testing and treatment can only go so far, said Prof O’Neal, since by the time symptoms arise, the patient may need urgent medical attention.
‘Continuous ketone monitoring provides a reading every 5 minutes without the person with diabetes needing to initiate the test, and these readings can be linked to an alarm.’
The technology is beginning to move closer to clinical use. In August 2026, the US Food and Drug Administration authorised Abbott’s Libre Rio 10 Day, a wearable device designed to continuously monitor both glucose and ketones.
Continuous ketone monitoring is not currently available to Australian patients.
‘Obviously, at some stage, we hope that these devices become available in this country,’ Prof O’Neal said.
‘[But] there’s regulatory approval and there’s accessibility. The people who need the devices need to be able to access them, and they need to be affordable.’
Patient education is another crucial factor.
‘People need to know how to understand the information that’s being provided by these devices and how to respond to it,’ Prof O’Neal said. ‘If ketones are rising, they need to not only recognise that’s the case, but they then need to be able to implement an intervention to reverse the ketosis. It is so much more than just handing over the device.’
Want to learn more about SGLT2 inhibitors? Complete this CPD on SGLT2 inhibitors in heart failure to build your knowledge.
