Carboxyhemoglobin elevation due to hemolytic anemia.

A critically ill man with drug-induced hemolytic anemia and hepatic failure was hospitalized at a private academic medical center in Seattle, Washington. Intravascular hemolysis with associated endogenous carbon monoxide (CO) production resulted in elevation of the patient's carboxyhemoglobin (COHb) level to as high as 9.7%. Serial measurements of the patient's COHb level were obtained and compared with other conventional measures of hemolytic activity. With the availability of new non-invasive measurement technology to detect COHb elevations, emergency clinicians are likely to see COHb elevation as a manifestation of hemolytic anemia.