Evaluation of a portable meter to measure ketonemia and comparison with ketonuria for the diagnosis of canine diabetic ketoacidosis.

BACKGROUND: The diagnosis of canine diabetic ketoacidosis (DKA) usually is based on measurement of urinary acetoacetate (ketonuria). In humans, this test is less sensitive and specific than blood 3-beta-hydroxybutyrate (ketonemia) evaluation.

HYPOTHESIS: Ketonemia measurement using a portable meter is more accurate than ketonuria determination with a dipstick to diagnose canine DKA.

ANIMALS: Seventy-two client-owned diabetic dogs with ketonemia, ketonuria, or both.

METHODS: Prospective observational study. Based on blood bicarbonate concentration and anion gap, dogs were divided into 2 groups: patients with DKA (n= 25); patients with diabetic ketosis (n= 47). Sensitivity, specificity, and positive and negative likelihood ratio (LR) at different cut-off points were determined for both ketonemia and ketonuria. Receiver operating characteristic (ROC) analysis was used to assess the accuracy of each diagnostic test to diagnose DKA.

RESULTS: With regard to ketonemia, cut-off values of 2.3 and 4.3 mmol/L revealed 100% sensitivity and 100% specificity, respectively, whereas cut-off values of 2.8 and 3.5 mmol/L showed a -LR of 0.05 and a + LR of 13.16, respectively. With regard to ketonuria, a cut-off value of 1+ revealed 92% sensitivity, 40% specificity, and -LR of 0.20, whereas a cut-off value of 3+ revealed 44% sensitivity, 94% specificity, and +LR of 6.89. The areas under the ROC curves for the ketonemia and ketonuria tests were significantly different (0.97 and 0.81, respectively, P= .003).

CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of ketonemia is accurate and more effective than measurement of ketonuria to diagnose canine DKA.