Postmortem Vitreous Humor Analysis in Dogs, Cats and Horses

Postmortem chemistry can be a useful ancillary technique that the forensic pathologist can use during a death investigation. In stark contrast, there is limited information available for use of postmortem vitreous humor analysis in animals. In order to use postmortem vitreous humor in veterinary forensic investigations, validation of a method to analyze vitreous humor is required. The goal of this study was to determine the precision, bias, TEobs and sigma (σ) of the Element DC chemistry analyzer; assess its precision using the vitreous humor collected postmortem from dogs, cats and horses and assess the stability of postmortem vitreous humor from all the three species. Analysis of quality control material (QCM) and pooled vitreous humor samples for the three species was used to test for sodium (Na), chloride (Cl), potassium (K), magnesium (Mg), creatinine (Crea) and blood/vitreous urea nitrogen. Analysis of QCM showed that the Element DC was both precise and accurate. When analyzing the pooled vitreous humors, most within-run coefficients of variance (CVs) were found to be <5% and the between-run CVs for five out of six analytes were found to be <5% for dogs, cats and horses. In all the three species, the capped samples of vitreous humor were stable out of refrigeration for up to 5 h. The results of this study show that the Element DC can successfully be used to analyze the postmortem vitreous humor from dogs, cats and horses.