From the Guidelines
Beta-hydroxybutyrate (BHB) is a better diagnostic test than serum ketones for detecting ketosis, particularly in diabetic ketoacidosis, due to its higher sensitivity and specificity.
Key Points
- BHB is the predominant ketone body produced during ketosis, accounting for approximately 80% of circulating ketones, making it more sensitive and specific for detecting clinically significant ketosis 1.
- Standard serum ketone tests primarily measure acetoacetate and acetone, which are present in lower concentrations and may not accurately reflect the true ketotic state.
- For clinical use, BHB levels above 0.5 mmol/L indicate mild ketosis, while levels exceeding 3.0 mmol/L suggest ketoacidosis requiring immediate medical attention.
- The physiological basis for BHB's superiority lies in its stability; unlike acetoacetate, BHB doesn't spontaneously degrade and remains stable in blood samples, providing more reliable results even when testing is delayed 1.
Clinical Recommendations
- BHB testing is recommended for diagnosing and monitoring diabetic ketoacidosis (DKA), as it provides a more accurate assessment of the ketotic state compared to serum ketone tests 1.
- BHB levels should be monitored every 2-4 hours during treatment of DKA to assess response to therapy and guide clinical decisions.
- The use of nitroprusside reaction-based blood ketone determinations should be avoided, as they do not measure BHB and may lead to inaccurate assessments of ketosis 1.
From the Research
Comparison of Diagnostic Tests for Ketosis
- Beta-hydroxybutyrate (BHB) is considered a better measurement of the degree of ketosis than serum ketones 2
- Studies have shown that BHB testing is more effective than urine acetoacetate testing in reducing emergency department assessment, hospitalization, and time to recovery from diabetic ketoacidosis 3
- BHB levels can be used to diagnose diabetic ketoacidosis, with threshold values of 3.0 mmol/L in children and 3.8 mmol/L in adults 4
- Point-of-care blood ketone testing using BHB meters can distinguish ketosis/ketoacidosis from simple hyperglycemia, with a blood ketone result of 3.5 mmol/L yielding 100% specificity and sensitivity for the diagnosis of diabetic ketoacidosis 5
- The diagnostic value of serum BHB in diabetic ketosis or diabetic ketoacidosis has been established, with an area under the ROC curve of 0.975 and a diagnostic point of 1 mmol/L (sensitivity 85.1%, specificity 95.3%) 6
Key Findings
- BHB is a more accurate and reliable diagnostic test for ketosis than serum ketones 2, 4, 6
- BHB testing can reduce the frequency of hospitalization and time to recovery from diabetic ketoacidosis 3
- Point-of-care blood ketone testing using BHB meters is a useful tool for distinguishing ketosis/ketoacidosis from simple hyperglycemia 5
- Serum BHB levels can be used to diagnose diabetic ketoacidosis, with a high degree of sensitivity and specificity 4, 6