Forensic Utility of Vitreous Potassium Concentration in Estimating Postmortem Interval: A Systematic Review

Area of Science:

• Forensic Pathology
• Biochemistry
• Toxicology

Background:

• Accurate estimation of postmortem interval (PMI) is crucial in forensic investigations.
• Biochemical markers offer a reliable method for PMI estimation, with vitreous potassium (K⁺) being a key analyte.
• Vitreous humor is favored due to its resistance to early decomposition and external factors.

Purpose of the Study:

• To systematically review and synthesize the evidence on the reliability of vitreous potassium for estimating PMI.
• To evaluate the correlation between vitreous potassium levels and PMI across various studies.
• To identify factors influencing the accuracy of vitreous potassium as a PMI indicator.

Main Methods:

• Systematic literature search of PubMed and Scopus databases.
• Inclusion of studies measuring vitreous potassium and assessing its relationship with PMI in human subjects.
• Analysis of 24 selected studies to evaluate correlation coefficients and regression models.

Main Results:

• Vitreous potassium showed a strong positive correlation with PMI (r = 0.84-0.99).
• A linear relationship was observed within the first 72 hours postmortem, with some studies reporting biphasic patterns.
• Significant variability in regression models was noted due to environmental conditions, analytical methods, and populations; temperature impacted reliability at extended PMIs.

Conclusions:

• Vitreous potassium is a valuable marker for PMI estimation, especially in early postmortem stages.
• Standalone accuracy is limited by variability; integration with other biochemical markers (e.g., hypoxanthine, albumin) enhances reliability.
• Multiparameter models incorporating vitreous potassium are recommended for improved forensic accuracy.