Final answer:
Standard Urine Drug Screens (UDS) may not detect certain synthetic opioids like fentanyl, tramadol, and methadone unless specific testing for these substances is included in the panel.
Step-by-step explanation:
The question pertains to a compound that might not be detected in a standard Urine Drug Screen (UDS). A standard UDS typically tests for common classes of drugs such as opiates, amphetamines, benzodiazepines, cocaine, marijuana, and PCP (phencyclidine). However, some synthetic opioids like fentanyl, tramadol, and methadone may not be detected by all standard urine drug tests unless additional specific testing is requested. It is important to know that each drug test can vary by the laboratory, the type of test used, and the substances included in the testing panel.