Metabolic
Ketones (beta-hydroxybutyrate)
Beta-hydroxybutyrate (BHB) is the dominant ketone body formed when metabolism shifts from glucose towards fat, for example during insulin deficiency, prolonged fasting or acute illness. Measuring it at the point of care gives a direct, quantitative read-out of ketosis from a single drop of capillary blood, faster and more informatively than a urine ketone dipstick.
Why it is measured
BHB rises early in diabetic ketoacidosis and is the principal ketone present in that state, so a quantitative bedside value supports rapid triage, severity grading and monitoring of the response to treatment. It is also used to gauge ketosis during illness, fasting or ketogenic regimens.
| Typical range | Adult capillary whole-blood BHB is typically below 0.6 mmol/L in the non-fasting state. Commonly used operational bands are: below 0.6 mmol/L normal, 0.6 to 1.5 mmol/L mild ketosis, 1.5 to 3.0 mmol/L increased risk, and above 3.0 mmol/L high risk consistent with developing or established ketoacidosis. Reportable ranges and cut-offs vary by device and method, so follow local protocol and the manufacturer's stated range. |
|---|---|
| Sample | Capillary whole blood from a fingerstick, typically about 1 microlitre dosed onto a single-use enzymatic beta-ketone test strip. Venous whole blood can also be applied on some systems. |
| Turnaround | Result in approximately 10 seconds once the strip is dosed. Most handheld blood beta-ketone strips report a quantitative value within about 10 seconds. |
Point of care devices that report it
- Abbott FreeStyle Optium Neo and Precision Xtra (Optium Xceed in some regions) using beta-ketone strips
- Nova Biomedical Nova Max Plus and StatStrip Glucose/Ketone meters
- A. Menarini Diagnostics GlucoMen LX PLUS with beta-ketone sensor
- EKF Diagnostics (Stanbio) STAT-Site WB beta-ketone and glucose analyser
Questions, answered
Why measure blood beta-hydroxybutyrate instead of urine ketones?
Urine dipsticks mainly detect acetoacetate and acetone, not BHB, which is the predominant ketone in ketoacidosis. Blood BHB gives a real-time quantitative value, whereas urine ketones lag behind the blood picture and can even appear to rise while a patient is actually improving. Blood testing is therefore generally preferred for assessing and monitoring ketosis. This is general information, not advice for an individual case.
Do different ketone meters give the same numbers?
All of these meters measure BHB enzymatically, but the reportable range, strip chemistry and calibration differ between systems, so values are not always interchangeable. Follow the cut-offs in the manufacturer's instructions for use and your local protocol, and avoid switching devices when trending the same patient. Run quality control as required by your point-of-care testing policy.
What blood BHB level is considered high?
Many services treat a capillary BHB above 1.5 mmol/L as a signal of significant ketosis and above 3.0 mmol/L as high risk for ketoacidosis, always interpreted alongside glucose, pH and the clinical picture. Exact thresholds vary by guideline and device. Any specific result must be interpreted by a qualified clinician in context, not from the number alone.