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NCJ Number: 136692 Add to Shopping cart Find in a Library
Title: Forensic Science: Immunoassay Drug Testing
Journal: Criminal Law Bulletin  Volume:28  Issue:2  Dated:(March-April 1992)  Pages:158-167
Author(s): E J Imwinkelried
Date Published: 1992
Page Count: 10
Sponsoring Agency: National Institute of Justice/
Rockville, MD 20849
NCJRS Photocopy Services
Rockville, MD 20849-6000
Sale Source: National Institute of Justice/
NCJRS paper reproduction
Box 6000, Dept F
Rockville, MD 20849
United States of America

NCJRS Photocopy Services
Box 6000
Rockville, MD 20849-6000
United States of America
Type: Legislation/Policy Analysis
Format: Article
Language: English
Country: United States of America
Annotation: This article discusses issues pertinent to the assessment of immunoassay drug testing as scientific evidence.
Abstract: Immunoassay techniques to test for the presence of specific drugs in the body rely on immunological principles. When various drugs enter the body, the immune system develops a protective antibody. Immunoassay techniques measure the presence of antibodies in the urine associated with particular drugs. There are several varieties of immunoassay including radioimmunoassay, enzyme multiplied or multiple immunoassay, and free radical assay. Although immunoassay evidence will likely be admitted even over an objection based on the Frye doctrine, such evidence is still vulnerable to "weight" attacks. Weight attacks are available whenever a prosecutor offers to prove that there was an illicit substance in the defendant's urine, the defendant consumed an illegal substance, or the defendant was impaired at a particular time. Immunoassay tests are nonspecific. They will yield positive test results with other substances because they are "cross-reactive" with other substances. False positives are so common that an attorney has much ammunition with which to persuade the trier of fact that a positive test does not establish the presence of an illegal substance in the defendant's urine. Further, unless the laboratory uses a realistically high cutoff value, the attorney may succeed in convincing the trier of fact that it is unwarranted to infer that the defendant consumed an illegal drug. It is certainly feasible for the attorney to persuade the trier of fact that the test by itself cannot prove that the defendant was impaired at a particular time. 47 footnotes
Main Term(s): Employee drug testing
Index Term(s): Drug testing; Rules of evidence; Urinalysis
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