The DRI Opiate Assay is a homogeneous enzyme immunoassay intended for the qualitative or semi-quantitative determination of opiates in human urine with 300 ng/mL or 2000 ng/mL as a cutoff calibrator.
The DRI® Opiate Assay is a homogeneous enzyme immunoassay using ready-to-use liquid reagents. The assay uses monoclonal antibodies that detect opiates in urine. The assay is based on the competition between an enzyme glucose-6-phosphate dehydrogenase (G6PDH) labeled drug and the free drug from the urine sample for a fixed amount of specific antibody binding sites. In the absence of free drug from the sample, the specific antibody binds the drug-labeled G6PDH and the enzyme activity is inhibited. This phenomenon creates a direct relationship between drug concentration in urine and the enzyme activity. The enzyme G6PDH activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.