Part I. The Analysis of Opiates in Blood. The Abbott TDx analyzer, which is marketed for the analysis of drugs in urine or serum, was applied to the detection and quantitation of total opiates in whole blood. The analysis was sensitive with a detection limit of about 30 ng/mL. The coefficient of variation in the determination was within 12% for the linear working range of 0-1000 ng/mL. The greatest merits of the method are speed and the small sample size. An analysis can be completed within 15 min and requires only 25 microL of sample. The method was applied to actual forensic cases and the results correlated well with derivative gas chromatography (r greater than 0.95). Interference effects of ethanol and dipipanone on the TDx measurements are reported. The method, similar to other immunoassays, is incapable of differentiating morphine and codeine. It was, however, shown to be a reliable screening technique. Part II. The Analysis of Opiates in Liver, Bile, and Urine. The Abbott TDx analyzer was applied to the detection and quantitation of total opiates in liver and bile without any sample pretreatment other than dilution with saline. No matrix effect was observed for liver. Bile matrices exerted negative interference, but this was overcome by a standard addition method. The analysis was sensitive with a detection limit of about 55 ng/g for liver. The detection limit for biles varied according to the extent of negative interference that the matrices exerted, but it was in the submicrogram per milliliter region.(ABSTRACT TRUNCATED AT 250 WORDS)