Postmortem Methanol and Formic Acid Levels and Their Pathological Correlates: Diagnostic Implications from an Autopsy Study

Background: Methanol poisoning remains a major cause of fatal toxic exposures worldwide, yet the diagnostic value of postmortem methanol and formic acid levels in relation to organ-specific pathology is not fully understood. This study aimed to provide a comprehensive forensic and diagnostic evaluation of fatal methanol intoxications using multiple biochemical and pathological parameters. Methods: A total of 138 autopsy-confirmed methanol poisoning cases were retrospectively analyzed. Quantitative methanol and formic acid levels were measured in blood and vitreous humor. Autopsy reports, demographic characteristics, and histopathological findings in major organs were systematically reviewed. The presence of ethanol and other substances, including stimulants and narcotic drugs, was also recorded. Results: Blood methanol concentrations averaged 142.47 ± 139.20 mg/dL (range: 0–595), and formic acid levels averaged 258.62 ± 197.89 mg/dL (range: 0–618). Vitreous humor concentrations showed comparable distributions. Common pathological findings included cerebral edema, putaminal discoloration or necrosis, myocardial ischemia, hepatic steatosis, pulmonary edema, and acute pancreatitis. Ethanol or other substances were detected in several cases, with stimulants or narcotic drugs present in 10.4% (n = 13). Importantly, the combined interpretation of postmortem biochemical markers and organ pathology allowed clearer differentiation of methanol-related injury patterns compared with prior reports. Conclusions: Methanol intoxication produces variable but characteristic biochemical and pathological profiles. Integrating toxicological markers with organ-specific pathology enhances the diagnostic accuracy of postmortem evaluations and supports more reliable identification of methanol-related deaths.