Abstract
In Reply.— The statement cited by Dr Fody requires some clarification. While it was meant to be associated primarily with the EMIT single-test assay, this was perhaps not clear. Unconfirmed positive results can occur due to technician errors or cross-reacting substances, and, in the case of marijuana, they can occur when the confirmation method is less sensitive than the screening method. This is frequently the case when immunoassay screens are used at their lower limits to assay for the many metabolites of THC in the aggregate and the confirmation method is assaying only for free 9-carboxy-THC, one of the metabolites that make up the mixture. This is probably the case for most of those false-positives reported in the cited literature above. This issue is discussed in the second paragraph of the Comment section of the article. This is not to imply that errors do not occur; where good quality control
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: JAMA: The Journal of the American Medical Association
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
