Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Since the introduction of SGLT2 inhibitors in approximately 2017 and the associated risk of euglycemic diabetic ketoacidosis¹, there have been rising numbers of blood ketone testing and referrals for interpretation of the result. We performed an audit of hospital fingerprick ketone testing at 4 NSW hospitals and uncovered a staggering rise over the last 7 years. Ketone measurements at St George Hospital alone have increased from <300 tests annually in 2017 to >18000 annually in 2023, with a similar trend in 3 other NSW hospitals, (Figure 1). Each capillary ketone strip costs $1. In contrast ketone testing has remained stable at the Sydney Children’s hospital over the last 4 years, in a population largely unaffected by the introduction of SGLT2 inhibitors. Interestingly, our audit did not reveal a rise in critical ketone levels with increasing test frequency. In 2017, 34% of ketone tests were >3mmol/L compared to only 6% in 2023. Where an elevated ketone level >3mmol/L was observed, the majority were paediatric patients. The remaining group consisted of patients fasting for a procedure, diabetic ketoacidosis or SGLT2i euglycemic ketoacidosis. We inexplicably found that the ward with the highest rate of ketone testing was the patient discharge lounge, a waiting room for patients awaiting transport home.

Following this audit, we reviewed hospital protocols for ketone testing. Preoperative protocols recommend ketone testing 4-hourly or ‘as clinically indicated’. As such, ketone testing has become a reflex rather than a conscious decision. We present an overview of the physiology of glucose metabolism and the utility of ketones as a vital energy source in the fasting state, allowing appreciation for the difference between mild fasting ketonemia and ketoacidosis. To improve clinical guidelines, we have proposed a table and flowchart that may be used to interpret and manage ketone results (Figure 2 and 3).