A comparison between carboxyhemoglobin and serum thiocyanate determinations as indicators of cigarette smoking.

Cigarette smoking histories were compared to carboxyhemoglobin and serum thiocyanate concentrations obtained from 426 smokers and 191 non-smokers. The mean levels of both carboxyhemoglobin and serum thiocyanate wefe significantly higher among cigarette smokers and correlated with number of cigarettes smoked per day. The specificity of both procedures was 81 per cent, and serum thiocyanate had a higher sensitivity (93 per cent vs. 83 per cent), making it potentially more suitable for use as an index of cigarette smoking.