Sample Preparation

Adsorption of cannabinoids by the surface of containers and equipment has been reported (Garrett and Hunt, 1974 Fenimore et al., 1976a Jones et al., 1984a Christophersen, 1986 Joern, 1987 Dextraze et al., 1989 Blanc et al., 1993 Bond et al., 1990 Dugan et al., 1994). Such adsorption of THC-COOH can lead to a lack of linearity in analysis (Joern, 1987) and is one explanation for loss of THC-COOH in storage (Jones et al., 1984a). Joern (1992c) reported that loss occurs from standard solutions of...

Info

COOH can vary for any given specimen donor that provides a sample at any given time. Therefore, the balance of analyte detection rate and confirmation rate for samples that exhibit GC MS values between the GC MS cutoff and immunoassay cutoff can differ from study to study. Smith-Kielland et al. (1999) demonstrated the relationship between the GC analysis of urinary THC-COOH concentration (using a 10 ng mL cutoff) and Syva Emit immunoassay values (using a 20 ng mL cutoff). The results were...

Blood Serum And Plasma

The detection and quantitative analysis of cannabinoids in blood, serum, and plasma are of interest for both pharmacological studies (Foltz et al., 1983) and forensic studies (Agurell et al., 1973). The possibility of correlating concentrations of THC and THC metabolites with time of consumption (Huestis et al., 1992a, 1992b) is of particular interest in traffic law enforcement and forensic cases since urinanalysis is not useful in determining whether the subject was under the influence at a...

Kinetic Interaction of Microparticles in Solution KIMS

The Roche (Indianapolis, IN) Abuscreen ONLINE and ONLINE DAT II products are KIMS-based immunoassays (Armbruster et al., 1993a, 1993b Hailer et al., 1995 Crouch et al., 1998b Boettcher et al., 2000). The cannabinoids qualitative applications utilize calibrators for cutoff at 20, 50, or 100ng mL, whereas the semiquantitative applications employ either four or five calibrators as appropriate for the respective cutoff levels. For example, calibrators 0, 20, 50, 100, and 300ng mL are used for the...

Stability Of Cannabinoids In Biological Fluids

Results obtained from any given immunoassay for drugs of abuse can be determined either by qualitatively comparing the resulting signal output of the specimen to that of the cutoff-level standard solution or by semiquantitative comparing to the calibration curve. Consequently, the stability of the analyte in calibrator solutions and in testing specimens is critical to the accuracy of the analytical system. The hydrophobic nature of the cannabinoids molecules can lead to the loss of the drugs in...

About The Authors

Athanaselis, Ph.D., received his BS in pharmacy from the University of Athens, Greece, in 1981. In 1982 he started to work as a scientific associate at the Department of Forensic Medicine and Toxicology, where today he holds the position of associate professor. He received his Ph.D. in toxicology in 1986 from the School of Pharmacy of the University of Athens after serving for 21 months in the Greek army. He has taught students of pharmacy, toxicology, and medical forensic...

Analytical Methods

Confirmation of THC-COOH by GC MS is by far the most widely used method, especially for forensic examination and for regulated analyses (Bronner and Xu, 1992 Goldberger and Cone, 1994 Badia et al., 1998a). However, a wide variety of methods are used in unregulated testing or in countries where regulated testing does not mandate mass spectrometry (Badia et al., 1998a). The use of TLC to identify THC-COOH is widespread in clinical laboratories and has substantial use in forensic laboratories...

Fluorescence Polarization Immunoassay Fpia

A variety of fluorescence-based immunoassays have been developed for clinical diagnostic applications. Fluorescence polarization (FP) was first applied to the competitive immunoassay of hapten molecules by Drandliker and colleagues (1961, 1970). The application of FPIA for therapeutic drug testing (TDM) was reported by Watson et al. (1976) and McGregor et al. (1978). Colbert and colleagues published a series of polarization fluoroimmunoassays for the detection of six classes of abused drugs in...

Enzyme Immunoassay

The utilization of enzymes as labels for antigen and antibody in immunological characterization started in the 1960s (Nakane and Pierce, 1967 Avrameas, 1968). Various formats of EIA have since been developed for a wide variety of applications. The most versatile EIA technique is the enzyme-linked immunosorbent assay (ELISA Engvall and Perlmann, 1971, 1972). The first homogeneous EIA developed for diagnostic applications is the enzyme-multiplied immunoassay technique (EMIT) (Rubenstein et al.,...

Review of Laboratory Testing

Cystolithic Hairs Marijuana

What follows is a review of much of the analytical literature from approximately the 1970s until the present regarding the testing of Cannabis and its constituents. The references generally fit within the seized-drug context. 3.1.2.2.1 Identification of Cannabis by Multiple Tests Traditionally, seized-drug identification of Cannabis relied on various combinations of wet chemical, microscopic, chromatographic, and spectroscopic testing methods. In recent years DNA profiling techniques for...

Cloned Enzyme Donor Immunoassay CEDIA

The Microgenics (Fremont, CA) CEDIA DAU Multi-Level THC assays can be used for qualitative or semiquantitative determinations of cannabinoids at 25, 50, or 100ng mL cutoff levels. The data analysis using the Roche Hitachi analyzers has been described in the previous section. The calibrators used for a 50 ng mL cannabinoids assay are 0, 25, 75, and 100ng mL. The performance of CEDIA for urine drug testing was compared to that of RIA, TDx, ONLINE, and EMIT II (Armbruster et al., 1995). Wu et al....

Onsite Pointofcollection Immunoassays

Various descriptions such as onsite, POC point of collection or point of care , rapid, and one-step drug tests have been applied to commercial non-instrument-based immunoassay kits for drugs-of-abuse testing Jenkins and Goldberger, 2002 . Ideally, onsite testing is the most convenient and effective way for abused-drug screening. Realistically, the technical challenges for devel Positive Specimen Drugs present in the specimen at or above the assay cutoff concentration Preliminary Positive Result...