title: Concentration ratios of methamphetamine to amphetamine in blood can help to distinguish use of methamphetamine from various mixtures of the two stimulants.
abstract: Using a forensic toxicology database, the authors investigated cases of driving under the influence of drugs (DUID) if methamphetamine (MA) was identified in the blood samples (N = 9,310). The concentrations of MA and amphetamine (AM) in blood were determined after liquid-liquid extraction by gas chromatography-mass spectrometry at limits of quantitation of 0.03 mg/L for both stimulants. In 814 cases, AM was negative in blood and MA was positive at mean (median) and highest concentrations of 0.19 mg/L (0.11 mg/L) and 3.4 mg/L, respectively. Both amines were present in blood in 8,496 cases at concentrations of 0.54 mg/L (0.35 mg/L) and 10.4 mg/L for AM and 0.41 mg/L (0.22 mg/L) and 5.6 mg/L for MA. However, the correlation between AM and MA was low and insignificant (r = -0.13) in the whole material. The coefficient of correlation increased to r = 0.41 (P < 0.001) when the MA/AM concentration ratio was >1. When MA/AM ratios were selected at intervals of 1.0 (e.g., >3.0 and <4.0 up to >9.0 and <10.0), the correlation between AM and MA was r = 0.99 (P < 0.001). Such cases represent the use of MA without contamination from AM, and the mean (median) and highest concentrations of this secondary amine in blood of DUID suspects were 0.72 mg/L (0.56 mg/L) and 4.2 mg/L, respectively.
authors.affiliation: Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden. wayne.jones@LIU.se
authors.forename: A W
authors.initials: AW
authors.lastname: Jones
authors.forename: A
authors.initials: A
authors.lastname: Holmgren
mesh_terms: D000661:Amphetamine / Q000097:blood*; D001334:Automobile Driving; D005260:Female; D053593:Forensic Toxicology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D059625:Liquid-Liquid Extraction; D008297:Male; D008694:Methamphetamine / Q000097:blood*; D015813:Substance Abuse Detection / Q000379:methods*; D013548:Sweden
chemical_list: D008694:Methamphetamine; D000661:Amphetamine