A long-term urinary metabolite of hydromorphone, a very potent opioid analgesic marketed under brand names including Palladone and Dilaudid. Hydromorphone is often used medicinally as an alternative to morphine for treatment of pain or as a cough suppressant for painful coughing resulting from continued bronchial irritation. This certified reference standard is suitable for use as a starting material in calibrators or controls for a variety of LC/MS or GC/MS applications from forensic analysis, clinical toxicology, and pain prescription monitoring to urine drug testing and pharmaceutical research.