Pseudoelevation of carboxyhemoglobin levels in firefighters.
Carbon monoxide is a common and potentially lethal exposure documented by an elevated carboxyhemoglobin (COHb) level. We conducted an investigation of unexpectedly high carboxyhemoglobin levels in a group of firefighters. Twelve of 34 (35%) nonsmokers tested had levels greater than 4% COHb and 9 of 34 (26%) had levels of 10% or higher. Quadruplicate blood samples from hospital staff and firefighters were sent in duplicate to the original laboratory, which used manual spectrophotometry, and to a second reference facility using a cooximeter. Cooximeter results were lower and also more reproducible. By cooximetry, all 24 nonsmoking firefighters retested had COHb levels less than 3%. Cooximetry is widely available and is the most suitable methodology in clinical situations. Spurious results despite the use of a large reference laboratory argue for the standardization of analytic methods for COHb among laboratories.
Kales
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Department of Medicine, Cambridge Hospital, MA 02139.
Pentiuc
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F
Christiani
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DC
D002249:Carbon Monoxide Poisoning / Q000097:blood* / Q000175:diagnosis; D002263:Carboxyhemoglobin / Q000032:analysis*; D005189:False Positive Reactions; D005390:Fires; D006801:Humans; D009784:Occupational Diseases / Q000097:blood* / Q000175:diagnosis; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods
D002263:Carboxyhemoglobin