Correlation of vitreous and serum biochemical markers with postmortem interval and cold storage duration: A prospective observational study

Estimating the postmortem interval is a critical yet challenging aspect of forensic investigations. This study investigates the potential of serum and vitreous humor (VH) biomarkers like CK-Total, CK-MB, urea, creatinine, and uric acid for PMI estimation, while also assessing the effect of cold chamber duration on these markers. A prospective observational study was conducted on 125 autopsy cases, with PMI ranging from 155 to 3540 min. Serum and VH samples were analyzed, and correlations between biomarker levels, PMI, and cold chamber duration were examined using Spearman's correlation. Significant positive correlations with PMI were found for serum CK-Total, CK-MB, and uric acid, while VH CK-Total and CK-MB also showed significant associations. In contrast, VH urea, creatinine, and uric acid did not correlate significantly with PMI. Serum biomarkers, particularly CK-MB, were also significantly associated with cold chamber duration. Regression models combining biomarker concentrations and cold storage time showed high predictive accuracy (R² = 0.9673 for serum and 0.986 for VH). The findings suggest that CK isoenzymes in serum, VH, and serum urea and uric acid are valuable for estimating PMI. Including cold chamber duration in the analysis further strengthens the reliability of these biomarkers, offering a robust approach for forensic applications.