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Posted on 8/20/2007 at 12:33 PM - Post CommentDetox products - Click HereAt the present time, there are a plethora of commercial assays and published methodologies that may be employed for drug testing. For the most part, these methods can be grouped into two categories, screening assays (tests) and confirmation assays. These assays can be adapted for measurement of drugs in body fluids, but they must first be properly validated. Generally, screening assays, such as immunoassays, are commercial-based tests that are inexpensive and simple to perform. In contrast, confirmation assays, such as gas chromatography/mass spectrometry (GC/MS), are more expensive and more labor intensive, but the sensitivity and specificity are generally higher than the screening assays. Immunoassay screening tests may cross-react with a variety of similar chemical substances, reducing their specificity. For example, most commercial immunoassays for opiates give positive test results for specimens containing either morphine, codeine or heroin metabolites. In this case, a more specific methodology, i.e. a confirmation assay, is needed to identify the particular drug or metabolite present. Often, the less expensive screening tests are employed initially to eliminate specimens containing no drug or drug below the cutoff concentration. The more expensive, labor intensive tests are subsequently employed for absolute drug identification and accurate quantification.
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