A Comparative Study of Ethanol Concentration in Costal Cartilage in Relation to Blood and Urine

Abstract

Blood is not always available in forensic autopsies, therefore, the search for alternative sampling materials is needed. This study aimed at examining if ethanol can be detected in costal cartilage and to investigate if different forms of costal cartilage can give accurate information about ethanol concentration in the blood or urine of human cadavers (n = 50). Ethanol concentration in samples of unground costal cartilage (UCC), ground costal cartilage (GCC), femoral venous blood, and urine was analyzed using a gas chromatography-flame ionization detector (GC-FID). Due to Polish law, we used two different cut-off points: the blood alcohol concentration >0.2 mg/mL defined as the ‘after use’ condition, and the blood alcohol concentration >0.5 mg/mL defined as the ‘state of insobriety’. Based on the constructed receiver operating characteristics (ROC) curves, the optimal cut-off point for ethanol content as the ‘after use’ condition was 0.273 mg/g for the UCC method and 0.069 mg/g for the GCC method. Analysis of the Areas under a ROC Curve (AUC) showed that both methods present excellent diagnostic accuracy (AUCUCC = 0.903; AUCGCC = 0.984). We demonstrated that it is possible to detect ethanol in the costal cartilage and showed that ethanol concentrations are determined in GCC samples with greater accuracy.