Simultaneous determination of carboxyhemoglobin and methemoglobin in victims of carbon monoxide poisoning.

Concentrations of methemoglobin (Met-Hb) and carboxyhemoglobin (HbCO) were simultaneously determined in blood samples from the victims of city gas poisoning, fires, and exhaust fumes poisoning. All the samples contained concentrations of HbCO, although the concentrations for victims of city gas poisoning were significantly higher than those for victims of fires or exhaust fumes poisoning. Only negligible amounts of Met-Hb were detected in the samples from cases of city gas poisoning, while 4.9 to 31.6% of Met-Hb were found in all but one (1.8%) of the samples of the other two cases. Heat denaturation was considered to be the main cause of Met-Hb production in cases of fires, and inhalation of oxides of nitrogen in cases of exhaust fumes poisoning.