Analysis of carbon monoxide.
The degree of exposure to carbon monoxide is most often assessed by measuring the blood carboxyhaemoglobin saturation. This measurement is relevant to investigations of acute accidental or deliberate poisoning and of chronic exposure in a domestic or work place environment. Simple spectrophotometric methods based on differential protein precipitation or dithionite reduction are prone to interference from other haemoglobin pigments and are imprecise for low-level estimations. Automated spectrophotometric devices (CO-oximeters) that estimate simultaneously total haemoglobin, percentage oxyhaemoglobin and percentage carboxyhaemoglobin have acceptable accuracy for carboxyhaemoglobin saturation levels of > 5% and are recommended for most clinical purposes. For the investigation of low-level exposure and the detection of increased haemolysis in neonates, more sensitive methods involving the release of carbon monoxide and its measurement by gas chromatography are required. Gas chromatographic methods are also appropriate when examining post-mortem blood samples where putrefaction or heat stress has resulted in a significant change in haemoglobin composition.
Medical Toxicology Unit, Guy's and St Thomas' Hospital NHS Trust, Avonley Road, London SE14 5ER, UK. brian.widdop@gstt.stthames.nhs.uk
Brian
B
Widdop
D001944:Breath Tests; D002248:Carbon Monoxide / Q000032:analysis* / Q000097:blood / Q000633:toxicity; D002249:Carbon Monoxide Poisoning / Q000097:blood / Q000175:diagnosis; D002263:Carboxyhemoglobin / Q000032:analysis; D019411:Clinical Laboratory Techniques; D006801:Humans; D011180:Postmortem Changes
D002248:Carbon Monoxide; D002263:Carboxyhemoglobin