The positive blood or urine result may only be the beginning. Toxicology tests, when properly performed, indicate use within a varying period of time depending on the drug and its dose. Metabolites of some drugs may remain in the urine for at least several days following a single dose. Thus the tests require interpretation and integration with other clinical information to give an opinion about the effects of a drug or combination of drugs on an individual at the time of the incident.
In the investigation of drugs or alcohol in a person’s system, forensic toxicologists must consider the possibility of tolerance, physical dependence, and other qualities that may bear on how meaningful is that positive result.
Toxicology tests do not disclose a pattern of use or the presence of dependence. The Forensic Panel’s expert toxicologist uses all available information, including the patient’s history, information from relatives, significant other, friends, or employers, physical examination and laboratory tests.
The time period of drug ingestion is a common point of contention, from our experience. A deep knowledge and understanding of testing methodology and the metabolism of drugs is an integral expertise of The Forensic Panel’s forensic toxicologists. Peer-review of the forensic toxicologist’s assessment ensures both objectivity and adherence to standards of toxicology, especially important in such technical matters that are well beyond the understanding of laypeople.