Clinical and Laboratory Standards Institute

Toxicology and Drug Testing in the Clinical Laboratory; Approved Guideline - Second Edition; Vol. 27 No. 15
 N C52-A2

Annotation

This guideline is intended to provide clinical laboratories with basic and general drug testing information for both clinical and forensic purposes. A reader of this document must recognize the difference between clinical and forensic drug testing and make a conscious decision about the type of testing that is conducted. Clinical laboratories may perform both types of drug testing as they are by no means mutually exclusive. However, the types of analytes tested, the way in which specimens are collected and maintained, the specifics of the analytical process, and the manner in which results are reported differ between clinical and forensic testing. The reader should recognize the legal standard required to perform forensic testing. While the analytical procedures for clinical and forensic drug testing are very similar, many nonanalytical details must be observed to conduct legally acceptable forensic analysis. Indeed, a clinical laboratory may find the documentation and laboratory security requirements so onerous that it will decide not to perform forensic testing. Ironically, while this guideline is intended to assist laboratories conducting forensic procedures, it will also serve its purpose if it dissuades laboratories that are ill prepared to meet the stringent mandates of forensic testing from entering that arena.

This guideline addresses the most common specimen types used for toxicology testing, including serum and plasma, whole blood, and urine. A wide variety of other specimen types are suitable for toxicological analysis, but they are not typically tested in routine clinical laboratories and are beyond the scope of this document.

Three general types of analytes are considered in this guideline: drugs of abuse, therapeutic drugs, and miscellaneous substances. Test methodologies include rapid screening assays designed to produce only positive or negative results (qualitative tests), routine semiquantitative and quantitative tests, and more complex confirmatory assays.