Traditional opiate immunoassays targeted codeine, morphine, and 6-acetylmorphine (the heroin marker) — and largely missed the semi-synthetic prescription opioids driving the opioid crisis. An expanded opiates (or "expanded opioids") panel closes that gap by adding hydrocodone, hydromorphone, oxycodone, and oxymorphone. DOT made this expansion mandatory in January 2018, changing the federal 5-panel’s "opiates" category to "opioids." For donors with valid prescriptions, the MRO verifies the prescription and reports the result negative — though the MRO may flag a safety concern to the employer when a medication could impair safety-sensitive work. Non-DOT employers can add the same expansion to any panel.