Determination of β- Hydroxybutyrate in B lood and Urine Using Gas Chromatography- Mass Spectrometry

β-Hydroxybutyrate (BHB) is considered a potential biomarker for alcoholic ketoacidosis (AKA). A r obust and sensitive method was developed and validated for the quantitative determination of BHB in postmortem blood and urine using deuterated γ-hydroxybutyrate as an internal standard. Samples were analyzed b y gas chromatography‐mass spectrometry following liquid‐liquid extraction and silyl derivatization. The limits of detection and lower limits of quantification in blood and urine were 2 and 7 mg/L and 2 and 6 mg/L, respectively. The interday and intraday precision was measured by coefficients of variation for blood and urine and ranged from 1.0 to 12.4% for quality control samples spiked at 50 and 300 mg/L. The linear range of 50‐500 mg/L resulted in an average correlation of R 2 > 0.99, and the average extraction recoveries in blood and urine were ≥ 82% and ≥ 59%, respectively. BHB remains stable in blood spiked at a concentration of 300 mg/L for 15 days when stored within a refrigerator (2‐5°C). Postmortem blood and urine samples were analyzed using the validated method for cases where the deceased had a history of chronic alcohol abuse to establish the use of BHB as a potential marker of AKA.