Carbon monoxide (CO) is one of the most toxic gases, responsible for a large number of deaths in the cases of smoke and fire burning. CO has the ability to combine reversibly with hemoglobin to form carboxyhemoglobin (HbCO), which denotes its chemical asphyxiant character. This leads to decreased oxygen carrying capacity of hemoglobin. Consequently, the determination of CO concentration and the degree of HbCO saturation in blood are frequently tested in toxicology laboratories. Recently, only the blood is considered the sample of choice for the detection of CO. Different methods for CO detection and estimation in blood have been employed including colorimetric screening, spectrophotometry and gas chromatography (GC). But when blood is not available in fire exposure postmortem cases, it is not possible to conclude the cause of death. Objective of this study is to highlight the significance of liver as specimen of interest in fatal carbon monoxide poisoning in relevance to detection in postmortem specimen of blood.

In this study, the authors considered data from one hundred and fifty fire burn cases for carbon monoxide detection. Among these cases, liver and blood were tested simultaneously for CO confirmation. These cases included confirmation of carbon monoxide using colorimetric a technique by palladium chloride micro diffusion assay in which metallic palladium is obtained after reduction of palladium chloride present in impregnated paper strips. The results were only considered positive if the strip develops black color strip with silver glitter. Carbon monoxide/drug-free whole blood was used as the negative control while 12% CO containing whole blood was used as a positive control.

One hundred and twenty-one (80.6%) cases were found positive for the presence of carbon monoxide both in blood and liver. Of these, 9.9% cases accounted for carbon monoxide detection only in blood. However, the remaining 9.5% of cases were found negative both for blood as well as liver.

Liver was positive for carbon monoxide in approximately 90.5% of the cases under test when the blood was also positive for these samples. As the heme is found both in blood and liver, so there is strong evidence of CO detection in liver. This will be a huge method for forensic investigations when the blood is unavailable but liver is available. This method will also be valuable for an exhumed putrefied postmortem sample when only liver is available.