Legal medicine (Tokyo, Japan)

Nicotine and cotinine levels in blood and urine from forensic autopsy cases.

PMID 15231285


We measured nicotine and cotinine levels in blood and urine from 31 forensic autopsy cases. Initially, we developed a sensitive and reproducible gas chromatographic method with a minimum limit of detection of 2.1 ng/ml for both nicotine and cotinine. Calibration curves for nicotine and cotinine were linear in the ranges of 2.1-1030 ng/ml (r2=0.994-0.999) and 2.1-1380 ng/ml (r2=0.998-0.999) respectively. Our population included 13 smokers and eight of these smokers committed suicide. They showed high levels of nicotine and cotinine at 65.1-205 ng/ml (mean: 115 ng/ml) and 31.3-938 ng/ml (mean: 405 ng/ml) in blood, respectively, and 234-7290 ng/ml (mean: 1940 ng/ml) and 143-4620 ng/ml (mean: 1170 ng/ml) in urine, respectively. None of these individuals consumed nicotine preparations or tobacco leaves. In five smokers who did not commit suicide, nicotine and cotinine levels were 4.4-62.1 ng/ml (mean: 33.2 ng/ml) and 49.9-217 ng/ml (mean: 140 ng/ml) in blood, respectively, and 158-314 ng/ml (mean: 246 ng/ml) and 68.9-300 ng/ml (mean: 179 ng/ml) in urine, respectively. Our results suggest that there may be a marked increase in consumption of cigarettes in smokers with suicidal thoughts.