Preliminary Evaluation of the Abbott TDx for Benzoylecgonine and Opiate Screening in Whole Blood*

Abstract

A method for the detection of benzoylecgonine (cocaine metabolite) and opiates in whole blood is described. This method employs the Abbott TDx fluorescence polarization immunoassay technique, which was designed for urine analysis. Drug-free whole blood was spiked with varying concentrations of benzoylecgonine, morphine, and codeine. Samples were prepared for analysis by adding 300 microL of 10% trichloroacetic acid to 300 microL of blood. Specimens were vortexed and centrifuged with 50 microL of supernatant required per assay. Precision studies of six replicate samples spiked with benzoylecgonine at 0.5 mg/L gave a within-run CV of 4.7% and a between-run CV of 4.7% with a detection limit of 0.1 mg/L. Within-run CVs for morphine at 0.5 mg/L and 0.1 mg/L were 1.7% and 7.9% respectively. The detection limits for morphine and codeine were 0.05 mg/L. Correlation coefficients for spiked whole blood calibration curves of benzoylecgonine, morphine, and codeine were 0.984, 0.999, and 0.997 respectively. This preliminary evaluation demonstrates a potential application of the TDx fluorescence polarization immunoassay technique to the analysis of drugs in whole blood.

The screening for common drugs of abuse in whole blood by means of EMIT-ETS and FPIA-ADx urine immunoassays

“…The FPIA urine assay was also adapted to blood without pretreatment [18] after precipitation with acetone [19] or trichloracetic acid [20]. FPIA serum lidocaine, phenobarbital and phenytoin assays, primarily designed for samples from living persons, were successfully used for examination of hemolytic serum or whole blood [21,22].…”

Préparation d’échantillons pour analyses en immunochimie

“…De nombreuses procédures sont disponibles dans la litté-rature pour la préparation du sang total : précipitation par le méthanol [4,5], l'acétone [6][7][8], l'acide trichloracétique [9], le dimethylformamide [10] ou encore le sulfate de zinc [11]. Une extraction liquide-liquide reste évidemment possible même si le temps d'extraction limite l'intérêt de l'utilisation de l'immunochimie par la suite.…”

Fluorescence Polarization Immunoassay for the Detection of Drugs of Abuse in Human Whole Blood

“…Therefore existing urine assays had been adapted for the examination of blood samples. Previously reported methods for the screening of whole blood for common drugs of abuse include EMIT and FPIA immunoassays after precipitation of the blood samples with either methanol (Peel et al, 1981;Asselin et al, 1988;Gjerde et al, 1990), acetone (Lewellen et al, 1988;Bogusz et al, 1990;Maier et al, 1992); N,N-dimethylformamide (Blum et al, 1989;Klinger et al, 1990), trichloroacetic acid (McCord, 1988) or liquidlliquid extraction (Slightom et al, 1978;Slightom et al, 1982). The purpose of this paper was to develop a method based on a homogenous immunoassay for the rapid screening of opiates, benzodiazepines, benzoylecgonine, barbiturates and methadone from autopsy, police and hospital blood samples.…”