Detection and Quantification of Carbon Monoxide in Postmortem Liver Tissues via Headspace GC-MS as an Alternative to Blood

Carbon monoxide (CO) is a gas that is readily absorbed by the lungs when inhaled. Once in the blood, it forms a complex with hemoglobin (Hb) in red blood cells known as carboxyhemoglobin (COHb), reducing the oxygen-carrying capacity of Hb and therefore disrupting the transport and delivery of oxygen throughout the body. The resulting lack of oxygen can be harmful and even lethal, making it important to be able to detect COHb in postmortem samples of relevant cases for determining a cause of death. Blood and spleen are the preferred specimens for the detection of CO because they are Hb rich, but these specimens may not always be available for collection during autopsy. This study aims to determine if liver tissue can be a reliable source for the detection and/or quantification of CO in postmortem specimens in the absence of blood or spleen. Liver homogenates and blood specimens from 25 postmortem cases with a positive CO result in blood (%COHb ≥10%) and 10 postmortem cases testing negative for CO in blood (%COHb <10%) were analyzed for COHb via headspace gas chromatography/ mass spectrometry (HS-GC-MS) and compared. Cases for which the blood produced a positive result for CO did not always result in a positive finding in the liver (%COHb ≥10%), even in cases with high levels of %COHb saturation (>50%). However, all cases that had a liver result ≥10% COHb had a corresponding blood result ≥10% COHb. If blood or spleen is not available for CO testing, liver may be tested as a potential indicator of CO exposure. A positive %COHb finding in the liver correlates with a positive %COHb result in blood, but negative results in liver are inconclusive and cannot rule out CO exposure.