Comparison of four immunoassays for the detection of lorazepam in urine.
Four healthy patient subjects were each given a single, 1-mg lorazepam tablet. Urine samples from all patient subjects were collected at 12 intervals (0-2, 2-5, 5-8, 8-11, 11-14, 14-24, 24-26, 26-29, 29-32, 32-35, 35-38, and 38-48 hours). An aliquot from each urine collection was screened using cloned enzyme donor immunoassay (CEDIA), enzyme-multiplied immunoassay technique (EMIT) II, EMIT dau, and fluorescence polarization immunoassay (FPIA) without and with hydrolysis using beta-glucuronidase. Using a 200 ng/mL calibrator cut-off, none of the four immunoassays gave a positive response before hydrolyzation of the urine samples. For offline hydrolysis using Helix pomatia beta-glucuronidase, 35, 3, 0, and 4 of 48 urine samples gave positive responses on the previously listed immunoassays. The CEDIA method also gave 32 of 48 positive responses for online hydrolysis using Escherichia coli beta-glucuronidase. Online hydrolysis can be conveniently automated by including the beta-glucuronidase in the first of the two reagents combined with the urine sample.
Meatherall
R
R
Biochemistry Laboratory, St. Boniface General Hospital, Winnipeg, Canada.
Fraser
A D
AD
D017248:Enzyme Multiplied Immunoassay Technique; D004926:Escherichia coli / Q000201:enzymology; D005260:Female; D016231:Fluorescence Polarization Immunoassay; D005966:Glucuronidase / Q000502:physiology; D006801:Humans; D006868:Hydrolysis; D007124:Immunoenzyme Techniques; D008140:Lorazepam / Q000652:urine*; D008297:Male; D012680:Sensitivity and Specificity; D013997:Time Factors
D005966:Glucuronidase; D008140:Lorazepam