Methods

Corp. & Roche) techniques for cannablnoid assay were evaluated. Authentic urine samples submitted for narcotics screening were analyzed for cannabinolds. All positive findings were confirmed by an HPLC procedure. The results indicated that the EMIT assay detects a few more positive samples, but also yields a higher rate of unconfirmed positive results compared to the TDx. Those additional "true " positives by EMIT had concentrations of the A=-THC-11-carboxylic acid below 10 ng/mL. In t roduct ion The established EM IT Cannabinoid assay (1,2) has been used for several years in our laboratory as a rapid screening test to detect cannabinoids in urine samples taken from prison i mates. Recently a new test, the TDx Cannabinoid Assay, utilizing fluorescence polarization (3) from Abbott was introduced in Sweden. To evaluate this procedure against the EMIT assay and to use an HPLC method (4) as a reference, the following studies were carried out " (1) Urine samples that tested positive for can-nabinoids by the EMIT-Cobas method and yielded an amount of the THC acid (A'-THC-1 l-carboxylic acid) above 20 ng/mL by HPLC were analyzed on the same day by the EMIT and the TDx assay. Qualitative results obtained from the immunoassays were compared. (2) Urine samples ubmitted for narcotics screening were randomly selected and analyzed by both the EMIT and the TDx assay. All positive samples according to results of the TDx and EMIT assays were analyzed by the HPLC method. In a separate study, the assay range and precision of the two immunoassays were compared