any member of the subphylum Crustacea (phylum Arthropoda), a group of invertebrate animals consisting of some 45,000 species distributed worldwide. Crabs, lobsters, shrimps, and wood lice are among the best-known crustaceans, but the group also includes an enormous variety of other forms without popular names.
It is thought that infrequent, low-dose users may test positive for Xanax within urine for up to 4 days post-ingestion. Frequent, high-dose users of the drug may test positive for Xanax after a full week post-ingestion via a urinalysis. Results from a urinalysis can be confirmed with technology such as GC/MS.
Xanax is a relatively short-acting drug when compared to Valium. If you're an average-size person, you would expect Xanax to stay in your urine for 1-4 days after last use. To be safe, you should wait at least a week.