Efficacy of plasma beta-hydroxybutyrate concentration as a marker for diabetes mellitus in acutely sick cats

Urine ketone measurement is routinely performed in cats with diabetes mellitus to identify impending or established ketoacidosis. Studies using the urinary ketone dipstick test have shown that ketonuria is common in cats with newly diagnosed untreated diabetes mellitus. This test has a low sensitivity as it quantifies the less abundant ketone acetoacetate. The objective of the present study was to determine if ketonaemia is an inherent biochemical finding in untreated feline diabetes mellitus by measuring plasma ss-hydroxybutyrate (ss-OHB) in acutely sick cats. In 122 sick cats (37 diabetic and 85 non-diabetic cats) plasma ss-OHB, glucose, fructosamine, total protein and thyroxine were measured as part of the routine work up. Diabetic cats had significantly elevated ss-OHB values and ss-OHB measurement was a sensitive and specific test to identify diabetes mellitus. The area under the receiver operating characteristic (ROC) curve was 0.93. The cut off value with the highest positive likelihood ratio was 0.58 mmol/l. These results suggest that determination of plasma ss-OHB concentration is a useful method to distinguish between diabetic and non-diabetic sick cats.