Normal Range of Beta-Hydroxybutyrate
The normal range for beta-hydroxybutyrate (BHB) in peripheral blood is 0.02 to 0.28 mmol/L, with levels below 0.6 mmol/L generally considered normal. 1
Established Reference Values
- Normal range: BHB levels of 0.02 to 0.28 mmol/L represent the physiologic baseline in healthy individuals 1
- Upper limit of normal: Values <0.6 mmol/L are considered within normal range and require no intervention 1, 2
Clinical Interpretation Thresholds Beyond Normal
Understanding the thresholds above normal is critical for recognizing pathologic states:
Mild to Moderate Ketosis
- BHB 0.6-1.5 mmol/L indicates mild to moderate ketosis requiring monitoring and possible intervention 1, 2
- This range serves as a caution threshold in diabetic patients, particularly during illness or with SGLT2 inhibitor use 1, 2
Significant Ketosis and DKA Risk
- BHB ≥1.5 mmol/L indicates significant ketosis with high risk for diabetic ketoacidosis (DKA) when accompanied by hyperglycemia and acidosis 1, 2, 3
- The American Diabetes Association recommends this threshold as diagnostic for DKA in the appropriate clinical context 2, 3
Severe Pathologic Ketoacidosis
- BHB >7-8 mmol/L indicates severe pathological ketoacidosis with profound acidosis requiring immediate medical attention 3
Age and Diabetic Status Considerations
The normal range (0.02-0.28 mmol/L, with <0.6 mmol/L as the upper threshold) applies universally across age groups 1. However, clinical interpretation differs based on diabetic status:
In Diabetic Patients
- Even mildly elevated BHB (≥0.6 mmol/L) warrants heightened vigilance 1, 2
- Patients at risk for DKA should measure BHB when blood glucose is persistently elevated (>250 mg/dL), during illness, or when symptoms of ketosis appear 2
- In type 1 diabetes, intense physical activity should be postponed when BHB ≥1.5 mmol/L due to risk of worsening ketosis 1, 2
SGLT2 Inhibitor Users
- These patients require particular attention as they can develop "euglycemic DKA" with normal or only mildly elevated blood glucose 1, 2
- Each 0.1 mmol/L increase in baseline BHB increases DKA risk by 18%, independent of treatment 4
Critical Measurement Considerations
- Direct blood BHB measurement is superior to urine ketone testing for diagnosing and monitoring ketoacidosis 1, 2, 3
- Standard urine dipsticks only detect acetoacetate, missing BHB entirely and significantly underestimating total ketone burden 3
- Negative urine ketone tests can occur despite elevated plasma BHB, particularly in poorly controlled diabetics 5