From the Guidelines
Beta hydroxybutyrate (BHB) levels should be interpreted based on the clinical context and testing purpose, with specific measurement of BHB in blood recommended for diagnosis and monitoring of diabetic ketoacidosis (DKA) 1.
Key Considerations
- Normal fasting levels are typically below 0.5 mmol/L.
- During nutritional ketosis from low-carbohydrate diets or intermittent fasting, levels between 0.5-3.0 mmol/L are expected and generally considered beneficial.
- For those managing diabetes, levels between 0.5-3.0 mmol/L may indicate effective fat metabolism, but should be monitored alongside blood glucose.
- Levels above 3.0 mmol/L warrant attention, while readings exceeding 5.0 mmol/L could indicate diabetic ketoacidosis in diabetic patients, requiring immediate medical attention 1.
Testing and Monitoring
- Blood ketone determinations that rely on the nitroprusside reaction should not be used to monitor treatment of DKA, as they do not quantify BHB, the predominant ketone in DKA 1.
- Blood ketone determinations that measure BHB specifically are useful for both diagnosis and ongoing monitoring of DKA.
- Regular monitoring of BHB helps track metabolic health and ketogenic diet effectiveness.
Clinical Context
- BHB serves as the body's alternative fuel when glucose is limited, providing efficient energy for the brain and muscles while reducing inflammation and oxidative stress.
- BHB rises naturally during fasting, with levels typically peaking after 3-5 days.
- For accurate readings, test at consistent times, preferably in the morning before eating.
From the Research
Interpreting Beta Hydroxybutyrate
To interpret beta hydroxybutyrate (BHB) levels, it is essential to consider the clinical context and the patient's medical history.
- BHB is a ketone body that can be measured in the blood to diagnose and monitor diabetic ketoacidosis (DKA) 2, 3, 4, 5.
- Elevated BHB levels can indicate ketosis, which is a complication of diabetes mellitus 2, 3, 5.
- The risk of DKA increases with incremental increases in baseline BHB and changes in BHB over time 3.
- BHB testing can be used to prevent and manage DKA in patients with Type 1 diabetes 4.
- Blood BHB testing is more effective than urine acetoacetate testing in reducing emergency department assessment, hospitalization, and time to recovery from DKA 4.
Clinical Significance of BHB Levels
- BHB levels can be used to diagnose DKA, with higher levels indicating a more severe condition 2, 3, 5.
- A BHB level > 0.6 mmol/L or > 1.5 mmol/L can be associated with an increased risk of DKA 3.
- BHB levels can also be used to monitor the effectiveness of treatment for DKA 2, 3, 4, 5.
- In addition to its role in diagnosing and monitoring DKA, BHB has important cellular signaling roles and can serve as an endogenous inhibitor of histone deacetylases (HDACs) and a ligand for cell surface receptors 6.
Factors Associated with BHB Levels
- Baseline BHB levels and changes in BHB over time are associated with an increased risk of DKA 3.
- Age, insulin pump use, and sotagliflozin use can also be associated with BHB levels and the risk of DKA 3.
- The clinical significance of BHB levels should be interpreted in the context of the patient's medical history, physical examination, and other laboratory results 2, 3, 4, 5.