Toxicological analysis of blood and urine samples from female victims of alleged sexual assault.

Background: The toxicological analysis of blood and urine samples from victims of alleged sexual assault represents a crucial part of the forensic evidence when this crime is investigated.
Material and Methods: We searched a national forensic toxicology database (TOXBASE) to find cases registered as sexual assault, rape, including date-rape that the police had requested the analysis of ethanol and other drugs. Between 2008 and 2010, N = 1460 such cases met this criteria. After immunological screening of urine or blood samples, all positive results were verified by more specific analytical methods, such as gas chromatography-mass spectrometry (GC-MS) for illicit drugs. A large number of prescription drugs and their metabolites were determined by capillary GC with nitrogen-phosphorous (N-P) detector. GC with flame ionization detector (FID) was used to analyze ethanol and gamma-hydroxybutyrate (GHB) in blood at limits of quantitation (LOQ) of 0.1 g/L and 8 mg/L, respectively.
Results: The average age (± standard deviation) of all victims was 24 ± 10.3 years and 72% were between 15 and 29 years. Ethanol and other drugs were not detected in 31% of cases (N = 459). Blood-ethanol was positive in N = 658 cases at mean, median and highest concentrations of 1.23 g/L, 1.22 g/L and 4.3 g/L, respectively. Ethanol plus drugs were present in N = 188 cases (13%) and one or more other drugs alone in N = 210 cases (14%). Cannabis (marijuana) and amphetamines were the major illicit drugs, whereas diazepam, alprazolam, zopiclone as well as newer antidepressants were the major prescription drugs identified.
Conclusions: The mean age of victims of sexual assault in Sweden, the proportion of drug positive to drug negative cases, the predominance of ethanol positive cases as well as the types of other drugs showed a remarkably good agreement in two studies spanning a period of 8 years.