Final answer:
Standard urine drug screens can detect commonly abused substances but may not identify newer synthetic drugs or certain prescription medications without specialized testing.
Step-by-step explanation:
The detection of drugs in a person's system depends significantly on the type of urine drug screen used, as well as the specifics of the drug itself, including its metabolism and half-life. Standard drug screens typically test for commonly abused substances like marijuana, cocaine, amphetamines, opiates, and phencyclidine (PCP). However, there are drugs that are not routinely detected by a basic urine drug screen, as these tests have a specific list of substances they are designed to detect. Newer synthetic drugs, certain prescription medications, and novel psychoactive substances might not be identified without specialized testing. It is crucial to understand that while a basic urine drug screen may not detect every possible drug, more comprehensive screens and other types of testing, such as blood or hair analysis, can identify a broader range of substances.