Indexed on: 01 Jul '98Published on: 01 Jul '98Published in: Rechtsmedizin
The extension of § 24 a of the road traffic regulations is expected to lead to more frequent investigations of blood for cannabinoids, opiates, cocaine (or metabolites) and amphetamines. Nearly 200 blood (serum) samples were analysed by the inhomogenous MTP-immunoassay for cannabinoids, opiates and amphetamines and 140 for cocaine consumption. In about half the specimens a gas chromatographic-mass spectrometric analysis followed. In generally immunassay results above 10 ng/ml for opiates, cannabinoids, or amphetamines and above 25 ng/ml for benzoylecgonine resulted in additional GC-MS analyses. Moreover cases with corresponding statements in the anamnesis were analysed gas-chromatographically otherwise only random tests were performed. Cannabinoids were detected in 47.4% of the samples, opiates in 31.1%, cocaine in 25.7% and amphetamines in 13.2%. The MTP-immunoassay has proved to be a good screening method to differentiate between probably positive and negative cases. In view of the threshold values above an offence is considered to have been proven, the results of our investigations result in Cut off values of 30 ng/ml with opiates and cannabinoids, 50 ng/ml with benzoylecgonine and 10 ng/ml with amphetamines. The tested assays have proven to be practicable and neglibable susceptible to interference. However it is recommendable to make a 3-point calibration before each series of samples.